Draw civil flights from an icon set moved on the GPU

Every flight is now a row in the layer's icon set. Its motion segment follows the same regime `_deadReckon` picks (interpolate between fixes, warm up backward from the oldest, coast forward from the newest), and one shared `_motionRegime` makes that choice for both. The shader moves every untracked contact between polls, so the 12 Hz fleet tick no longer touches each billboard. It now only re-plans expired rows, floors grounded contacts, advances focus while needed, and runs the 3D model regime. Grounded contacts the floor lifts are pinned to a hold at the floored position. Their nose glides on the GPU. Contacts within 50 km re-floor every tick, and farther ones take turns about once a second. Low contacts are judged for the horizon at no lower than 12 m above the ellipsoid, as before. Below hover speed a contact's nose holds. A row whose fleet model is drawn keeps its focus updated, because the model reads it. Untracking re-plans and re-floors the icon from the tracked course. On the same views with about 6,700 OpenSky flights, frame gaps at p95 drop from 28-40 ms to 17 ms, and the fleet tick from 16-37 ms to about 2 ms at most.
2026-11-07 20:04:00 +00:00 · 2026-11-03 19:40:39 -08:00
1 parent 5f36eb0e0d
commit 2c4c66c710
@@ -1315,6 +1315,12 @@
      "src/layers/flights/policy.js",
      "src/layers/flights/queries.js",
      "src/layers/flights/rendering.js",
+      "src/layers/flights/icons.js",
+      "src/data/iconSetPrimitive.js",
+      "src/data/iconSet.js",
+      "src/data/iconSegment.js",
+      "src/data/iconAtlas.js",
+      "src/data/aircraftRecession.js",
      "src/data/modelMirror.js",
      "src/data/billboardMirror.js",
      "src/layers/aircraft/visualState.js",
@@ -2249,6 +2255,7 @@
      "./standalone/catalog"
    ],
    "modules": [
+      "src/layers/flights/icons.js",
      "src/sources/adsbFields.js",
      "src/data/headingDegrees.js",
      "src/data/distanceFormat.js",
@@ -3248,6 +3255,11 @@
  "application-layer-construction": {
    "exports": ["./application/layers"],
    "modules": [
+      "src/layers/flights/icons.js",
+      "src/data/iconSetPrimitive.js",
+      "src/data/iconSet.js",
+      "src/data/iconSegment.js",
+      "src/data/iconAtlas.js",
      "src/sources/adsbFields.js",
      "src/data/headingDegrees.js",
      "src/data/distanceFormat.js",
@@ -252,6 +252,8 @@ const _b64 = (s) =>
 *  NEAR the display size lets the browser's SVG AA do the work: crisp AND
 *  smooth. 64 covers the 40–58 px fleet band with ≤1.6× minification. */
 const FLEET_RASTER_PX = 64;
+/** Raster size of the default fleet glyph. */
+export const FLEET_ICON_PX = FLEET_RASTER_PX;
 /** Tracked raster: the tracked billboard is the one SUSTAINED large 2D glyph
 *  (close-zoom fleet flybys hand off to 3D models). Keep the 192 px texture so
 *  it stays crisp at its biggest on-screen sizes. */
@@ -243,6 +243,40 @@ export function applyAircraftBillboardTreatment({
  return _treatmentResult;
 }

+/**
+ * The alpha an aircraft draws with: base × max(combined floor, focus × limb
+ * haze). Icon sets compose the same thing in their shader; models need it here.
+ * @param {object} input
+ * @param {number} input.baseAlpha
+ * @param {number} input.focusFactor
+ * @param {number} input.cameraDistanceM
+ * @param {number} input.cameraHeightM
+ * @param {Partial<typeof DEFAULT_AIRCRAFT_RECESSION_PARAMS>} [input.params]
+ * @returns {number}
+ */
+export function aircraftTreatmentAlpha({
+  baseAlpha,
+  focusFactor,
+  cameraDistanceM,
+  cameraHeightM,
+  params,
+}) {
+  const tuning = resolvedParams(params);
+  const factors = aircraftRecessionFactorsResolved(
+    cameraDistanceM,
+    cameraHeightM,
+    tuning,
+    _scratchFactors,
+  );
+  return (
+    baseAlpha *
+    Math.max(
+      tuning.combinedAlphaFloor,
+      clamp(focusFactor, 0, 1) * factors.alpha,
+    )
+  );
+}
+
 /**
 * Apply layer-owned hue and composed aircraft alpha to an ambient glTF model without
 * disturbing Cesium's existing MIX/colorBlendAmount presentation semantics.
@@ -83,24 +83,24 @@ for (const layer of LAYERS) {
  test(`${layer.name}: near AIR state is independent from model admission`, () => {
    assert.match(source, /nextCockpitNearContacts\(/,
      'Cockpit derives a separate near-contact hysteresis set');
-    assert.match(source, /isCockpitContact && !isCockpitNear[\s\S]*cockpitContactDotImage\(\)/,
+    assert.match(source, /isCockpitContact && !isCockpitNear[\s\S]*cockpitContactDotImage\(\)|!flightState\._cockpitNearContacts\.has\(icao24\);\s*if \(cockpitDot\) \{\s*const dot = iconAtlas\.slot\(cockpitContactDotImage\(\)/,
      'only out-of-range Cockpit contacts become dots');
    // `_iconKind` is identity for every unconverted contact (see
    // tr3bRegistry.test.mjs) — it only swaps the glyph for a contact the
    // operator explicitly converted into a TR-3B.
-    assert.match(source, /bb\.image\s*=\s*aircraftIcon\(\s*_iconKind\(\s*icao24,\s*meta\?\.klass,?\s*\)(,\s*aircraftVisuals\.read\(bb\)\?\.iconLarge\s*\?\s*TRACKED_ICON_PX\s*:\s*undefined)?,?\s*\)/,
+    assert.match(source, /bb\.image\s*=\s*aircraftIcon\(\s*_iconKind\(\s*icao24,\s*meta\?\.klass,?\s*\)(,\s*aircraftVisuals\.read\(bb\)\?\.iconLarge\s*\?\s*TRACKED_ICON_PX\s*:\s*undefined)?,?\s*\)|aircraftIcon\(\s*parts\.rendering\._iconKind\(icao24, info\?\.klass\),?\s*\)/,
      'near contacts and model fallbacks retain the class-derived aircraft silhouette');
-    assert.match(source, /setBillboard\(\s*bb,\s*'rotation',\s*0\s*\);/,
+    assert.match(source, /setBillboard\(\s*bb,\s*'rotation',\s*0\s*\);|set\.setFlag\(row, ICON_ROTATES, false\);/,
      'far dots are reset to a rotation-free presentation');
-    assert.match(source, /\(\s*!(?:flightState\.)?_cockpitContactMode\s*\|\|\s*isCockpitNear,?\s*\)\s*&&\s*\(\s*doRotations\s*\|\|\s*revealed,?\s*\)/,
+    assert.match(source, /\(\s*!(?:flightState\.)?_cockpitContactMode\s*\|\|\s*isCockpitNear,?\s*\)\s*&&\s*\(\s*doRotations\s*\|\|\s*revealed,?\s*\)|set\.setFlag\(row, ICON_ROTATES, true\);/,
      'near 2D silhouettes continue to receive projected course');
-    assert.match(source, /if\s*\(\s*billboardState\(bb\)\.show,?\s*\)\s*setBillboard\(\s*bb,\s*'show',\s*false\s*\);\s*\/\/\s*hand\s*off\s*ONLY\s*once\s*the\s*model\s*renders/,
+    assert.match(source, /if\s*\(\s*billboardState\(bb\)\.show,?\s*\)\s*setBillboard\(\s*bb,\s*'show',\s*false\s*\);\s*\/\/\s*hand\s*off\s*ONLY\s*once\s*the\s*model\s*renders|icons\.setShown\(row, false\);\s*\/\/\s*hand\s*off\s*ONLY\s*once\s*the\s*model\s*renders/,
      'the gap-proof billboard-to-model handoff remains intact');
  });

  test(`${layer.name}: Cockpit exit clears near state before restoring map presentation`, () => {
    const setMode = /^([ \t]*)function _setCockpitContactMode\b[\s\S]*?\n\1\}/m.exec(source)?.[0];
    assert.match(setMode, /else\s*(?:flightState\.)?_cockpitNearContacts\s*=\s*new\s*Set\(\s*,?\s*\);/);
-    assert.match(setMode, /for\s*\(\s*const\s*\[icao24,\s*bb\]\s*of\s*(?:flightState\.)?_billboards,?\s*\)\s*(?:parts\.\w+\.)?_applyFleetBillboardPresentation\(\s*icao24,\s*bb,?\s*\);/);
+    assert.match(setMode, /for\s*\(\s*const\s*\[icao24,\s*bb\]\s*of\s*(?:flightState\.)?_billboards,?\s*\)\s*(?:parts\.\w+\.)?_applyFleetBillboardPresentation\(\s*icao24,\s*bb,?\s*\);|for \(let row = 0; row < \(icons\?\.count \?\? 0\); row\+\+\)\s*parts\.icons\._applyIconPresentation\(icons\.idAt\(row\)\);/);
  });
 }
@@ -40,5 +40,9 @@ export const _driveFleetModelHandoffForTest =
  flightsLayer.testing._driveFleetModelHandoffForTest;
 export const _ensureFleetModelForTest =
  flightsLayer.testing._ensureFleetModelForTest;
+export const _iconForTest = flightsLayer.testing._iconForTest;
+export const _setIconForTest = flightsLayer.testing._setIconForTest;
+export const _floorGroundedIconsForTest =
+  flightsLayer.testing._floorGroundedIconsForTest;
 export const mapAnalystRecord = flightsLayer.mapAnalystRecord;
 export default flightsLayer;
@@ -14,6 +14,8 @@ import flightsLayer, {
  _setTrackedFlightRefreshStateForTest,
  _floorGroundedDisplayPositionForTest,
  _clearDisplayFloorStateForTest,
+  _iconForTest,
+  _floorGroundedIconsForTest,
  mapAnalystRecord,
 } from './flights.js';
 import { setMilitaryLayerActive } from './militaryRegistry.js';
@@ -225,18 +227,9 @@ test('nonempty OpenSky payload with zero usable rows cannot prove share target a
 test('a newly seen aircraft appears at its delayed position, not ahead of it', async () => {
  // The fleet renders RENDER_DELAY_SEC behind real time, so a fresh contact's
  // first displayed position is its fix projected back to that delayed time.
-  // Creating the billboard at the raw fix drew it ahead until the next fleet
+  // Creating the icon at the raw fix drew it ahead until the next fleet
  // tick, which then jumped it back about one delay of travel.
-  const added = [];
-  const billboardCollection = {
-    show: false,
-    add(options) {
-      const billboard = { ...options };
-      added.push(billboard);
-      return billboard;
-    },
-    remove() {},
-  };
+  const billboardCollection = { show: false };
  const viewer = { camera: { positionCartographic: null }, scene: {} };
  _setTrackedFlightRefreshStateForTest({
    icao24: 'seed00',
@@ -293,9 +286,9 @@ test('a newly seen aircraft appears at its delayed position, not ahead of it', a
  };
  try {
    await flightsLayer.update(viewer);
-    const billboard = added.find((entry) => entry.id === icao24);
-    assert.ok(billboard, 'the new contact gets a billboard');
-    const shown = Cesium.Cartographic.fromCartesian(billboard.position);
+    const icon = _iconForTest(icao24);
+    assert.ok(icon, 'the new contact gets an icon');
+    const shown = Cesium.Cartographic.fromCartesian(icon.position);
    const fix = Cesium.Cartesian3.fromDegrees(fixLon, fixLat, 10_700);
    const behindM = Cesium.Cartesian3.distance(
      Cesium.Cartesian3.fromRadians(shown.longitude, shown.latitude, 10_700),
@@ -1066,21 +1059,12 @@ const _floorCarto = (pos) =>

 test('a newly seen taxiing aircraft starts on the floor under its delayed position', async () => {
  // A grounded contact is drawn at its delayed position lifted onto the floor
-  // under it. Creating the billboard without that lift started it on the
+  // under it. Creating the icon without that lift started it on the
  // floor of its reported fix, then the next fleet tick raised it.
  _clearDisplayFloorStateForTest();
  _clearMeshFloorCellsForTest();
  setMeshFloorPreferred(true);
-  const added = [];
-  const billboardCollection = {
-    show: false,
-    add(options) {
-      const billboard = { ...options };
-      added.push(billboard);
-      return billboard;
-    },
-    remove() {},
-  };
+  const billboardCollection = { show: false };
  const viewer = { camera: { positionCartographic: null }, scene: {} };
  _setTrackedFlightRefreshStateForTest({
    icao24: 'seed00',
@@ -1142,9 +1126,9 @@ test('a newly seen taxiing aircraft starts on the floor under its delayed positi
  };
  try {
    await flightsLayer.update(viewer);
-    const billboard = added.find((entry) => entry.id === icao24);
-    assert.ok(billboard, 'the new contact gets a billboard');
-    const shown = _floorCarto(billboard.position);
+    const icon = _iconForTest(icao24);
+    assert.ok(icon, 'the new contact gets an icon');
+    const shown = _floorCarto(icon.position);
    assert.ok(
      Cesium.Math.toDegrees(shown.longitude) < fixLon,
      'drawn behind the fix',
@@ -1160,6 +1144,95 @@ test('a newly seen taxiing aircraft starts on the floor under its delayed positi
  }
 });

+test('far grounded contacts take turns on the floor; near ones refloor every tick', async () => {
+  // The floor pass is the fleet tick's only per-contact CPU work. Past
+  // FLOOR_NEAR_M a contact is refloored once per FLOOR_FAR_EVERY_TICKS.
+  _clearDisplayFloorStateForTest();
+  _clearMeshFloorCellsForTest();
+  setMeshFloorPreferred(true);
+  const viewer = { camera: { positionCartographic: null }, scene: {} };
+  _setTrackedFlightRefreshStateForTest({
+    icao24: 'seed00',
+    entity: null,
+    billboard: {
+      show: false,
+      position: Cesium.Cartesian3.fromDegrees(0, 0, 0),
+    },
+    billboardCollection: { show: false },
+    viewer,
+    meta: { rawLat: 0, rawLon: 0, onGround: false },
+    tracked: false,
+  });
+  const icao24 = 'taxi02';
+  const fixLon = -97.66;
+  const fixLat = 30.2;
+  for (let k = -40; k <= 40; k += 1) {
+    reportMeshFloorCell(fixLat, fixLon + k * 0.0001, 131.5);
+  }
+  const nowSec = Math.floor(Date.now() / 1000);
+  const realFetch = globalThis.fetch;
+  globalThis.fetch = async (url) => {
+    if (!String(url).startsWith('/api/flights')) {
+      return { ok: true, status: 200, json: async () => ({ ac: [] }) };
+    }
+    return {
+      ok: true,
+      status: 200,
+      headers: { get: () => null },
+      json: async () => ({
+        time: nowSec,
+        states: [
+          [
+            icao24,
+            'TAXI02 ',
+            'United States',
+            nowSec - 2,
+            nowSec - 2,
+            fixLon,
+            fixLat,
+            null,
+            true,
+            10,
+            90,
+            0,
+            null,
+            null,
+            null,
+            null,
+            null,
+            5,
+          ],
+        ],
+      }),
+    };
+  };
+  try {
+    await flightsLayer.update(viewer);
+    const start = Cesium.JulianDate.now();
+    const at = (s) =>
+      Cesium.JulianDate.addSeconds(start, s, new Cesium.JulianDate());
+    const far = Cesium.Cartesian3.fromDegrees(fixLon, fixLat, 3_000_000);
+    const near = Cesium.Cartesian3.fromDegrees(fixLon, fixLat, 10_000);
+    let last = _iconForTest(icao24).position;
+    const moves = (camera, from, to) => {
+      let count = 0;
+      for (let tick = from; tick <= to; tick += 1) {
+        _floorGroundedIconsForTest(at(tick), camera);
+        const now = _iconForTest(icao24).position;
+        if (Cesium.Cartesian3.distance(now, last) > 1) count += 1;
+        last = now;
+      }
+      return count;
+    };
+    assert.equal(moves(far, 1, 24), 2, 'far: once per 12 ticks');
+    assert.equal(moves(near, 25, 30), 6, 'near: every tick');
+  } finally {
+    globalThis.fetch = realFetch;
+    _clearMeshFloorCellsForTest();
+    _clearDisplayFloorStateForTest();
+  }
+});
+
 test('display floor: a grounded contact that drifted onto a higher cell is lifted', () => {
  _clearDisplayFloorStateForTest();
  _clearMeshFloorCellsForTest();
@@ -45,7 +45,7 @@ const COURSE0 = 19; // deg
 const COURSE_SLOPE = 20; // lerp: deg per unit fraction
 const SLEW_OFFSET = 21; // deg still to glide at SLEW_T0
 const SLEW_T0 = 22; // s
-const SLEW_RATE = 23; // deg/s
+const SLEW_RATE = 23; // deg/s; negative holds the course at the glide's start

 const DEG = Math.PI / 180;
 const STRAIGHT_BELOW_RAD_PER_SEC = 1e-4;
@@ -140,6 +140,8 @@ export function writeArcSegment(out, row, segment) {
 /**
 * Glide the displayed course from `fromCourseDeg` onto the segment's own course,
 * at most `rateDps`, starting at `t0` (the rate limit at a segment boundary).
+ * A rate of zero or less holds `fromCourseDeg` for the whole segment instead
+ * (a hover: the nose keeps its heading however the track moves).
 * Call after writing the segment.
 * @param {Float32Array} out
 * @param {number} row
@@ -153,7 +155,7 @@ export function writeCourseGlide(out, row, fromCourseDeg, t0, rateDps) {
  const target = targetCourse(out, o, t0);
  out[o + SLEW_OFFSET] = norm180(fromCourseDeg - target);
  out[o + SLEW_T0] = t0;
-  out[o + SLEW_RATE] = Math.max(0, rateDps);
+  out[o + SLEW_RATE] = rateDps > 0 ? rateDps : -1;
 }

 /**
@@ -195,6 +197,8 @@ export function segmentCourse(seg, row, tau) {
  const o = row * SEGMENT_STRIDE;
  const course = targetCourse(seg, o, tau);
  const offset = seg[o + SLEW_OFFSET];
+  if (seg[o + SLEW_RATE] < 0)
+    return norm360(targetCourse(seg, o, seg[o + SLEW_T0]) + offset);
  if (offset === 0) return norm360(course);
  // limitCourseStep: the displayed course turns at the rate toward the segment's
  // own (possibly turning) course until it reaches it, then follows it. The
@@ -207,6 +211,17 @@ export function segmentCourse(seg, row, tau) {
  return norm360(turned < gap ? start + offset + toward * turned : course);
 }

+/**
+ * The course the row glides toward at `tau` (its segment's own course).
+ * @param {Float32Array} seg
+ * @param {number} row
+ * @param {number} tau
+ * @returns {number}
+ */
+export function segmentTargetCourse(seg, row, tau) {
+  return norm360(targetCourse(seg, row * SEGMENT_STRIDE, tau));
+}
+
 /** The segment's own course at `tau`, before any glide. */
 function targetCourse(seg, o, tau) {
  const kind = seg[o + KIND];
@@ -310,6 +325,7 @@ float iconTargetCourse(vec4 seg3, vec4 seg4, vec4 seg5, float tau) {
 float iconSegmentCourse(vec4 seg3, vec4 seg4, vec4 seg5, float tau) {
  float course = iconTargetCourse(seg3, seg4, seg5, tau);
  float offset = seg5.y;
+  if (seg5.w < 0.0) return iconTargetCourse(seg3, seg4, seg5, seg5.z) + offset;
  if (offset == 0.0) return course;
  float toward = -sign(offset);
  float start = iconTargetCourse(seg3, seg4, seg5, seg5.z);
@@ -213,3 +213,35 @@ test('the course glide never outruns the rate while its target turns', () => {
    'then it follows the turn',
  );
 });
+
+test('a zero-rate glide holds the course however the segment turns', () => {
+  const seg = new Float32Array(SEGMENT_STRIDE);
+  const to = Cesium.Cartesian3.fromDegrees(-97.04, 32.90001, 10_500);
+  for (const from of [0, 30]) {
+    writeLerpSegment(seg, 0, {
+      from: fix,
+      to,
+      t0: 0,
+      t1: 30,
+      course0Deg: 0,
+      courseSlopeDeg: 90,
+    });
+    writeCourseGlide(seg, 0, from, 0, 0);
+    for (const tau of [0, 10, 20, 30, 60])
+      assert.ok(
+        courseGap(segmentCourse(seg, 0, tau), from) < 1e-4,
+        `from ${from}° at τ=${tau}`,
+      );
+  }
+  writeArcSegment(seg, 0, {
+    fix,
+    t0: 0,
+    minDt: 0,
+    maxDt: 300,
+    speedMps: 1,
+    trackDeg: 90,
+    turnRateDps: 3,
+  });
+  writeCourseGlide(seg, 0, 90, 0, 0);
+  assert.ok(courseGap(segmentCourse(seg, 0, 20), 90) < 1e-4, 'arc turn held');
+});
@@ -43,8 +43,14 @@ export const ICON_SHOWN = 1;
 export const ICON_ROTATES = 2;
 /** Fade and shrink toward the globe's limb (aircraft recession). */
 export const ICON_RECEDES = 4;
-/** Lift the row 12 m along the normal before the horizon test (fixes near the ground). */
+/**
+ * Judge the row at no lower than ICON_CULL_HEIGHT_M above the ellipsoid in the
+ * horizon test. A fix near or below the ellipsoid (a grounded contact at geoid
+ * −31 m before its floor warms) otherwise reads as beyond the limb.
+ */
 export const ICON_CULL_LIFT = 8;
+/** The ellipsoid height a CULL_LIFT row is raised to for the horizon test. */
+export const ICON_CULL_HEIGHT_M = 12;

 /** Move the epoch forward once render times pass this many seconds. */
 const REBASE_AFTER_SEC = 1800;
@@ -422,6 +428,24 @@ export function createIconSet({ capacity = 1024, epoch } = {}) {
    course(row, tau) {
      return segmentCourse(segments, row, tau);
    },
+    /** The point the horizon test judges for a row drawn at `position`. */
+    cullPoint(row, position, result = new Cesium.Cartesian3()) {
+      if (!(style[row * STYLE_STRIDE + FLAGS] & ICON_CULL_LIFT))
+        return Cesium.Cartesian3.clone(position, result);
+      // Height above the ellipsoid along the geocentric ray, as the shader
+      // computes it: exact to millimetres this close to the surface.
+      const radius = Cesium.Cartesian3.magnitude(position);
+      Cesium.Cartesian3.multiplyComponents(
+        position,
+        Cesium.Ellipsoid.WGS84.oneOverRadii,
+        result,
+      );
+      const height = radius * (1 - 1 / Cesium.Cartesian3.magnitude(result));
+      const lift = Math.max(0, ICON_CULL_HEIGHT_M - height);
+      Cesium.Cartesian3.normalize(position, result);
+      Cesium.Cartesian3.multiplyByScalar(result, lift, result);
+      return Cesium.Cartesian3.add(position, result, result);
+    },
  };

  function markRow(row) {
@@ -4,6 +4,8 @@ import * as Cesium from 'cesium';
 import {
  createIconSet,
  DirtyRows,
+  ICON_CULL_HEIGHT_M,
+  ICON_CULL_LIFT,
  ICON_ROTATES,
  ICON_SHOWN,
 } from './iconSet.js';
@@ -225,3 +227,25 @@ test('rebasing moves the epoch without moving any row', () => {
  assert.equal(set.expires(row), 1100);
  assert.deepEqual(set.dirty.segments.runs(set.count), [[0, 0]]);
 });
+
+test('a cull-lift row is judged at no lower than the cull height above the ellipsoid', () => {
+  const set = createIconSet();
+  const row = set.add('a');
+  const height = (p) => Cesium.Cartographic.fromCartesian(p).height;
+  const at = (h) => Cesium.Cartesian3.fromDegrees(-84.43, 33.64, h);
+  assert.ok(
+    Math.abs(height(set.cullPoint(row, at(-31))) - -31) < 1e-6,
+    'unflagged: as drawn',
+  );
+  set.setFlag(row, ICON_CULL_LIFT, true);
+  for (const h of [-31, 0, 5]) {
+    assert.ok(
+      Math.abs(height(set.cullPoint(row, at(h))) - ICON_CULL_HEIGHT_M) < 0.01,
+      `${h} m is judged at ${ICON_CULL_HEIGHT_M} m`,
+    );
+  }
+  assert.ok(
+    Math.abs(height(set.cullPoint(row, at(131))) - 131) < 1e-6,
+    'a contact floored higher keeps its own height',
+  );
+});
@@ -16,7 +16,7 @@
 */
 import * as Cesium from 'cesium';
 import { ICON_SEGMENT_GLSL, SEGMENT_STRIDE } from './iconSegment.js';
-import { ICON_CULL_LIFT, STYLE_STRIDE } from './iconSet.js';
+import { ICON_CULL_HEIGHT_M, ICON_CULL_LIFT, STYLE_STRIDE } from './iconSet.js';
 import { iconAtlas, MAX_ICON_SLOTS } from './iconAtlas.js';
 import {
  cameraLimbDistanceM,
@@ -25,8 +25,6 @@ import {

 /** On-screen device pixels above which a row draws its near (large) image. */
 const NEAR_IMAGE_PX = 76;
-/** Rows lifted this far before the horizon test when flagged (low fixes). */
-const CULL_LIFT_M = 12;

 const ATTRIBUTE_LOCATIONS = Object.freeze({
  corner: 0,
@@ -80,6 +78,13 @@ bool iconFlag(float flags, float bit) {
  return mod(floor(flags / bit), 2.0) == 1.0;
 }

+// Raise a near-ground point to at least the cull height (iconSet.cullPoint).
+vec3 iconCullPoint(vec3 world) {
+  float radius = length(world);
+  float height = radius * (1.0 - 1.0 / length(world * czm_ellipsoidInverseRadii));
+  return world + world / radius * max(0.0, ${ICON_CULL_HEIGHT_M.toFixed(1)} - height);
+}
+
 bool occludedByEllipsoid(vec3 world) {
  vec3 cv = u_horizon.xyz;
  float vh2 = u_horizon.w;
@@ -101,7 +106,7 @@ void main() {

  vec3 rte = iconSegmentPosition(seg0, seg1, seg2, seg3, seg4, u_tau);
  vec3 world = u_cameraPosition + rte;
-  vec3 cullPoint = iconFlag(flags, ${ICON_CULL_LIFT.toFixed(1)}) ? world + normalize(world) * ${CULL_LIFT_M.toFixed(1)} : world;
+  vec3 cullPoint = iconFlag(flags, ${ICON_CULL_LIFT.toFixed(1)}) ? iconCullPoint(world) : world;
  if (occludedByEllipsoid(cullPoint)) return;

  vec4 positionEC = czm_modelViewRelativeToEye * vec4(rte, 1.0);
@@ -1660,7 +1660,7 @@ test('hasContact declines while a layer is disabled, whatever its maps still hol
    [
      'flights',
      readLayerSource(new URL('./flights.js', import.meta.url)),
-      /hasContact\(\s*icao24,?\s*\)\s*\{\s*\n\s*if\s*\(\s*!(?:flightState\.)?_billboardCollection\s*\|\|\s*!(?:flightState\.)?_billboardCollection\.show\s*\|\|\s*(?:flightState\.)?_billboards\.size\s*===\s*0,?\s*\)\s*return\s*null;/,
+      /hasContact\(\s*icao24,?\s*\)\s*\{\s*\n\s*const icons = flightState\._icons;\s*\n\s*if\s*\(\s*!icons\s*\|\|\s*!icons\.show\s*\|\|\s*icons\.count\s*===\s*0,?\s*\)\s*return\s*null;/,
    ],
    [
      'militaryFlights',
@@ -10,7 +10,10 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import * as Cesium from 'cesium';
-import flightsLayer, { _setTrackedFlightRefreshStateForTest } from './flights.js';
+import flightsLayer, {
+  _iconForTest,
+  _setTrackedFlightRefreshStateForTest,
+} from './flights.js';
 import militaryFlightsLayer, { _setTrackedMilitaryRefreshStateForTest } from './militaryFlights.js';

 const ICAO = 'abc123';
@@ -39,6 +42,8 @@ const LAYERS = [
    name: 'commercial',
    layer: flightsLayer,
    visualCenterM: Cesium.Cartesian3.ZERO,
+    // Where the icon is drawn: the seeded position as the GPU encodes it.
+    spritePosition: () => _iconForTest(ICAO).position,
    seed({ billboardShow, models = [] }) {
      _setTrackedFlightRefreshStateForTest({
        icao24: ICAO,
@@ -61,6 +66,7 @@ const LAYERS = [
    name: 'military',
    layer: militaryFlightsLayer,
    visualCenterM: Cesium.Cartesian3.ZERO,
+    spritePosition: () => contactBillboard(true).position,
    seed({ billboardShow, models = [] }) {
      _setTrackedMilitaryRefreshStateForTest({
        icao24: ICAO,
@@ -149,8 +155,8 @@ for (const fixture of LAYERS) {
    const spritePosition = detectionPosition(fixture.layer);
    assert.ok(spritePosition, 'the 2D sprite publishes a detection candidate');
    assert.ok(
-      Cesium.Cartesian3.equalsEpsilon(spritePosition, contactBillboard(true).position, 0, 1e-6),
-      'the 2D bracket stays welded to the billboard position',
+      Cesium.Cartesian3.equalsEpsilon(spritePosition, fixture.spritePosition(), 0, 1e-6),
+      'the 2D bracket stays welded to the drawn sprite position',
    );

    const modelMatrix = Cesium.Matrix4.fromRotationTranslation(MODEL_ROTATION, MODEL_POSITION);
@@ -195,7 +201,7 @@ for (const fixture of LAYERS) {
    const loadingPosition = detectionPosition(fixture.layer);
    assert.ok(loadingPosition, 'the billboard remains detectable while its model loads');
    assert.ok(
-      Cesium.Cartesian3.equalsEpsilon(loadingPosition, contactBillboard(true).position, 0, 1e-6),
+      Cesium.Cartesian3.equalsEpsilon(loadingPosition, fixture.spritePosition(), 0, 1e-6),
      'a shown-but-unready zero-scale model cannot steal the detection anchor',
    );
  });
@@ -3,7 +3,6 @@ import test from 'node:test';
 import * as Cesium from 'cesium';
 import { routePlausible } from './routePlausible.js';
 import { createTracking } from '../layers/flights/tracking.js';
-import { addBillboard } from './billboardMirror.js';

 const SFO = { lat: 37.6188, lon: -122.3754, code: 'SFO' };
 const LAX = { lat: 33.9416, lon: -118.4085, code: 'LAX' };
@@ -116,15 +115,14 @@ test('unjudgeable endpoint geometry and missing coordinates keep the loose contr
  assert.equal(plausible(beyond, null, null), true);
 });

-test('the actual native tracked label hides the wrong leg and keeps a healthy route', (t) => {
-  const collection = new Cesium.BillboardCollection();
-  t.after(() => collection.destroy());
+test('the actual native tracked label hides the wrong leg and keeps a healthy route', () => {
  const flightState = {
    records: { data: new Map(), missingPolls: new Map() },
    feed: { _backoff: false },
-    _billboards: new Map(),
    _scratchCarto: new Cesium.Cartographic(),
  };
+  // Where each contact's icon is drawn.
+  const drawn = new Map();
  // Only application host services are supplied. Route admission, WGS84
  // billboard conversion and tracked-label formatting are the actual owners.
  const services = Object.fromEntries(
@@ -141,7 +139,10 @@ test('the actual native tracked label hides the wrong leg and keeps a healthy ro
    ].map((name) => [name, {}]),
  );
  services.aircraftPresentation = { isTr3b: () => false };
-  const parts = { queries: { _contactLabel: (_, info) => info.callsign } };
+  const parts = {
+    queries: { _contactLabel: (_, info) => info.callsign },
+    icons: { _iconPosition: (id) => drawn.get(id) ?? null },
+  };
  const tracking = createTracking({ flightState, services, parts });
  for (const [position, expected] of [
    [beyond, false],
@@ -155,18 +156,9 @@ test('the actual native tracked label hides the wrong leg and keeps a healthy ro
      verticalRate: 0,
      route,
    });
-    flightState._billboards.set(
+    drawn.set(
      id,
-      addBillboard(collection, {
-        id,
-        width: 20,
-        height: 20,
-        position: Cesium.Cartesian3.fromDegrees(
-          position.lon,
-          position.lat,
-          10000,
-        ),
-      }),
+      Cesium.Cartesian3.fromDegrees(position.lon, position.lat, 10000),
    );
    assert.equal(
      tracking._trackedLabelText(id).includes('SFO → LAX'),
@@ -233,7 +233,7 @@ test('both flight layers keep a converted contact 2D and visible (render invaria

    // 1. The 3D model handoff is SUPPRESSED for a converted contact — there is
    //    no TR-3B GLB, so the triangle billboard stays the visual.
-    assert.match(source, /modelEligible\.has\(icao24\) && !isTr3b\(icao24\)/,
+    assert.match(source, /modelEligible\.has\(icao24\) && !isTr3b\(icao24\)|for \(const icao24 of modelEligible\) \{\s*if \(isTr3b\(icao24\)\) continue;/,
      `${name}: fleet model handoff skips converted contacts`);
    // The tracked regime became default-on and camera-distance driven
    // (2026-08-19), so the suppression moved from a conjunct on
@@ -245,7 +245,7 @@ test('both flight layers keep a converted contact 2D and visible (render invaria
    // 2. The billboard is never hidden by that suppression — it must keep
    //    satisfying the getNearby/getDetectableObjects visibility guards, so a
    //    converted contact still works in Contacts and Cockpit.
-    assert.match(source, /if\s*\(\s*(bb|modelled)\s*&&\s*id\s*!==\s*(?:flightState\.)?_trackedIcao,?\s*\)\s*setBillboard\(\s*\1,\s*'show',\s*true,?\s*\);/,
+    assert.match(source, /if\s*\(\s*(bb|modelled)\s*&&\s*id\s*!==\s*(?:flightState\.)?_trackedIcao,?\s*\)\s*setBillboard\(\s*\1,\s*'show',\s*true,?\s*\);|if\s*\(\s*row >= 0\s*&&\s*id\s*!==\s*flightState\._trackedIcao\s*\)\s*flightState\._icons\.setShown\(row, true\);/,
      `${name}: converting restores the billboard the model handoff had hidden`);

    // 3. Every aircraftIcon() CALL SITE routes through the kind resolver, so no
@@ -411,7 +411,7 @@ test('a converted contact never consumes a 3D model CAP SLOT', async () => {
    const source = readLayerSource(new URL(`./${name}`, import.meta.url));
    // Anchor on the MODEL-eligibility loop (keepDistSq), not the unrelated
    // ambient-enrichment candidate loop that also builds a `cand`.
-    const loop = /const\s*cand\s*=\s*\[\];\s*\n\s*for\s*\(\s*const\s*\[icao,\s*bb\]\s*of\s*(?:flightState\.)?_billboards,?\s*\)[\s\S]*?cand\.push\(\s*/.exec(source)?.[0];
+    const loop = /const\s*cand\s*=\s*\[\];\s*\n\s*for\s*\((?:\s*const\s*\[icao,\s*bb\]\s*of\s*(?:flightState\.)?_billboards,?\s*|let row = 0; row < icons\.count; row\+\+)\)[\s\S]*?cand\.push\(\s*/.exec(source)?.[0];
    assert.ok(loop, `${name}: the model-eligibility candidate loop is present`);
    assert.match(loop, /keepDistSq/, `${name}: matched the model-eligibility loop`);
    assert.match(loop, /if \(isTr3b\(icao\)\) continue;/,
@@ -34,6 +34,8 @@ import flightsLayer, {
  _trackedBillboardColorForTest as flightsTrackedBillboardColor,
  _driveFleetModelHandoffForTest as flightsDriveFleetModel,
  _ensureFleetModelForTest as flightsEnsureFleetModel,
+  _iconForTest as flightsIcon,
+  _setIconForTest as flightsSetIcon,
 } from './flights.js';
 import militaryFlightsLayer, {
  _setTrackedMilitaryRefreshStateForTest,
@@ -186,6 +188,25 @@ function contactBillboard() {
  };
 }

+/** A flights contact's icon row, read and written the way these tests read a
+ *  billboard: where it is drawn and whether the layer shows it. */
+function flightIconView(icao24) {
+  return {
+    get position() {
+      return flightsIcon(icao24)?.position;
+    },
+    set position(position) {
+      flightsSetIcon(icao24, { position });
+    },
+    get show() {
+      return flightsIcon(icao24)?.shown === true;
+    },
+    set show(shown) {
+      flightsSetIcon(icao24, { shown });
+    },
+  };
+}
+
 /** Records what the driver hands to the scene, so a test can assert that a
 *  failing loader never put a model up. */
 function recordingModelCollection() {
@@ -216,7 +237,7 @@ const LAYERS = [
        modelCollection,
        meta: { callsign: 'TEST123 ', altitude: 10_668, klass: 'airliner', onGround },
      });
-      return billboard;
+      return flightIconView(icao24);
    },
  },
  {
@@ -9,7 +9,6 @@ import {
  ENRICH_AMBIENT_REFILL_WINDOW_MS,
  ENRICH_AMBIENT_PER_SWEEP,
 } from './policy.js';
-import { billboardState } from '../../data/billboardMirror.js';

 export function createEnrichment({
  flightState,
@@ -94,9 +93,7 @@ export function createEnrichment({
          });
          if (klass !== meta.klass) {
            meta.klass = klass;
-            const bb = flightState._billboards.get(icao24);
-            if (bb)
-              parts.rendering._applyFleetBillboardPresentation(icao24, bb);
+            parts.icons._applyIconPresentation(icao24);
            // Hangar fleet: the class's GLB/scale may have changed — resync the
            // live model, any in-flight load, and the tracked standalone model.
            parts.rendering._syncModelToClass(icao24);
@@ -182,8 +179,7 @@ export function createEnrichment({
    if (
      flightState._enrichAmbientBudget <= 0 ||
      !flightState._viewer ||
-      !flightState._billboardCollection ||
-      !flightState._billboardCollection.show
+      !flightState._icons?.show
    )
      return;
    try {
@@ -196,13 +192,19 @@ export function createEnrichment({
        camera.upWC,
      );
      const cand = [];
-      for (const [icao24, bb] of flightState._billboards) {
+      const icons = flightState._icons;
+      const tau = parts.icons._displayTau();
+      for (let row = 0; row < icons.count; row++) {
+        const icao24 = icons.idAt(row);
        if (flightState._enrichSeen.has(`t:${icao24}`)) continue; // answered / queued / negative this session
        if (!/^[0-9a-f]{6}$/i.test(icao24)) continue; // adsbdb keys are 6-char hex only
        if (flightState.records.data.get(icao24)?.onGround) continue; // ground traffic never spends ambient budget (click-to-enrich still works)
-        const { position } = billboardState(bb);
-        if (!position || !occluder.isPointVisible(position)) continue; // beyond the limb
-        Cesium.Cartesian3.clone(position, flightState._scratchModelBS.center);
+        const position = icons.position(
+          row,
+          tau,
+          flightState._scratchModelBS.center,
+        );
+        if (!occluder.isPointVisible(position)) continue; // beyond the limb
        if (
          cull.computeVisibility(flightState._scratchModelBS) ===
          Cesium.Intersect.OUTSIDE
@@ -1,11 +1,11 @@
 import * as Cesium from 'cesium';
-import { aircraftIcon } from '../../data/aircraftIcons.js';
 import { FOCUS_EVIDENCE_DEV } from './policy.js';
+import { writeHoldSegment } from '../../data/iconSegment.js';
 import {
-  addBillboard,
-  billboardState,
-  setBillboard,
-} from '../../data/billboardMirror.js';
+  aircraftRecessionFactors,
+  aircraftTreatmentAlpha,
+} from '../../data/aircraftRecession.js';
+import { horizonOccluder } from '../../data/iconOrientation.js';

 export function createEvidence({
  flightState,
@@ -44,17 +44,14 @@ export function createEvidence({
  /** Replace the real fleet with deterministic explicit-position contacts. */

  function _setFocusEvidenceAircraft(records = []) {
-    if (
-      !FOCUS_EVIDENCE_DEV ||
-      !flightState._billboardCollection ||
-      !flightState._viewer
-    )
+    if (!FOCUS_EVIDENCE_DEV || !flightState._icons || !flightState._viewer)
      return { ok: false, count: 0 };
    if (flightState._trackedIcao) parts.tracking._clearTracking();
    parts.rendering._releaseModels();
-    for (const bb of flightState._billboards.values())
-      flightState._billboardCollection.remove(bb);
-    flightState._billboards.clear();
+    const icons = flightState._icons;
+    icons.clear();
+    flightState._grounded.clear();
+    flightState._floorPinned.clear();
    flightState.records.data.clear();
    flightState._positionHistory.clear();
    flightState._displayCourse.clear();
@@ -86,32 +83,19 @@ export function createEvidence({
        rawLon: record.longitude ?? null,
      };
      flightState.records.data.set(id, meta);
-      flightState._cullPositions.delete(id);
      flightState._focusEvidenceIds.add(id);
-      const bb = addBillboard(flightState._billboardCollection, {
-        position,
-        image: aircraftIcon(parts.rendering._iconKind(id, klass)),
-        width: 20,
-        height: 20,
-        scale: parts.rendering._fleetBillboardScale(id, klass),
-        rotation: 0,
-        alignedAxis: Cesium.Cartesian3.ZERO,
-        color: parts.rendering._fleetBillboardColor(id),
-        sizeInMeters: false,
-        scaleByDistance: parts.rendering._normalBillboardScaleByDistance(),
-        disableDepthTestDistance: parts.rendering._groundDepthDistance(),
-        id,
-        show: true,
-      });
-      flightState._billboards.set(id, bb);
+      parts.icons._addIcon(id);
+      const row = icons.row(id);
+      writeHoldSegment(icons.segments, row, position, meta.true_track);
+      icons.segmentWritten(row);
    }
-    flightState.feed._count = flightState._billboards.size;
+    flightState.feed._count = icons.count;
    flightState._lastFleetTickMs = 0;
    flightState._viewer.scene.requestRender?.();
    return { ok: true, count: flightState.feed._count };
  }

-  /** Update explicit evidence positions without rebuilding billboards. */
+  /** Update explicit evidence positions without rebuilding rows. */

  function _moveFocusEvidenceAircraft(records = []) {
    if (!FOCUS_EVIDENCE_DEV) return { ok: false, moved: 0 };
@@ -122,15 +106,21 @@ export function createEvidence({
        .toLowerCase();
      if (!flightState._focusEvidenceIds.has(id)) continue;
      const position = _focusEvidencePosition(record);
-      const bb = flightState._billboards.get(id);
-      if (!position || !bb) continue;
-      setBillboard(bb, 'position', position);
+      const row = flightState._icons?.row(id) ?? -1;
+      if (!position || row < 0) continue;
      const meta = flightState.records.data.get(id);
      if (meta) {
        if (Number.isFinite(record.trackDeg)) meta.true_track = record.trackDeg;
        if (Number.isFinite(record.velocityMps))
          meta.velocity = record.velocityMps;
      }
+      writeHoldSegment(
+        flightState._icons.segments,
+        row,
+        position,
+        meta?.true_track ?? 0,
+      );
+      flightState._icons.segmentWritten(row);
      moved += 1;
    }
    flightState._lastFleetTickMs = 0;
@@ -142,27 +132,42 @@ export function createEvidence({

  function _focusEvidenceSnapshot() {
    if (!FOCUS_EVIDENCE_DEV || !flightState._viewer) return [];
+    const icons = flightState._icons;
+    const { scene, camera } = flightState._viewer;
+    const occluder = horizonOccluder(camera);
+    const cameraHeightM = camera.positionCartographic?.height;
    return [...flightState._focusEvidenceIds].map((id) => {
-      const bb = flightState._billboards.get(id);
-      const screen = billboardState(bb)?.position
-        ? Cesium.SceneTransforms.worldToWindowCoordinates(
-            flightState._viewer.scene,
-            billboardState(bb).position,
-          )
+      const row = icons?.row(id) ?? -1;
+      const position = row < 0 ? null : parts.icons._iconPosition(id);
+      const cameraDistanceM = position
+        ? Cesium.Cartesian3.distance(camera.positionWC, position)
+        : null;
+      const screen = position
+        ? Cesium.SceneTransforms.worldToWindowCoordinates(scene, position)
+        : null;
+      // What the icon shader composes: base scale × limb taper, and base
+      // alpha × max(floor, focus × limb haze).
+      const factors = position
+        ? aircraftRecessionFactors({ cameraDistanceM, cameraHeightM })
        : null;
      return {
        id,
-        show: billboardState(bb)?.show === true,
-        scale: billboardState(bb)?.scale ?? null,
-        alpha: bb?.color?.alpha ?? null,
+        show:
+          !!position &&
+          icons.shown(row) &&
+          parts.icons._aboveHorizon(row, position, occluder),
+        scale: factors ? icons.scale(row) * factors.scale : null,
+        alpha: position
+          ? aircraftTreatmentAlpha({
+              baseAlpha: icons.alpha(row),
+              focusFactor: icons.focus(row),
+              cameraDistanceM,
+              cameraHeightM,
+            })
+          : null,
        x: screen?.x ?? null,
        y: screen?.y ?? null,
-        cameraDistanceM: billboardState(bb)?.position
-          ? Cesium.Cartesian3.distance(
-              flightState._viewer.camera.positionWC,
-              billboardState(bb).position,
-            )
-          : null,
+        cameraDistanceM,
      };
    });
  }
@@ -0,0 +1,471 @@
+import * as Cesium from 'cesium';
+import {
+  COURSE_HOLD_SPEED_MPS,
+  courseBetweenCartesians,
+  courseSlewCapDps,
+  norm180,
+  speedRamp,
+  staleCoastLimitSeconds,
+} from '../../data/motionModel.js';
+import {
+  createIconSet,
+  ICON_CULL_LIFT,
+  ICON_RECEDES,
+  ICON_ROTATES,
+} from '../../data/iconSet.js';
+import {
+  segmentCourse,
+  segmentTargetCourse,
+  writeArcSegment,
+  writeCourseGlide,
+  writeHoldSegment,
+  writeLerpSegment,
+} from '../../data/iconSegment.js';
+import { IconSetPrimitive } from '../../data/iconSetPrimitive.js';
+import { iconAtlas } from '../../data/iconAtlas.js';
+import {
+  aircraftIcon,
+  FLEET_ICON_PX,
+  TRACKED_ICON_PX,
+} from '../../data/aircraftIcons.js';
+import { cockpitContactDotImage } from '../../data/cockpitContactDot.js';
+import { horizonOccluder } from '../../data/iconOrientation.js';
+import {
+  COCKPIT_CONTACT_SIZE_PX,
+  COURSE_MAX_DPS,
+  FLOOR_FAR_EVERY_TICKS,
+  FLOOR_NEAR_M,
+  RENDER_DELAY_SEC,
+} from './policy.js';
+
+/** Raster size of the cockpit contact pip (cockpitContactDot.js draws 16 px). */
+const COCKPIT_DOT_PX = 16;
+/** Pinned grounded rows rewrite only past this displayed move (m²) or turn (°). */
+const PIN_MOVE_SQ_M = 1;
+const PIN_TURN_DEG = 0.1;
+
+/**
+ * The flights layer's contacts as one icon set: each row's motion segment
+ * mirrors `_deadReckon`'s regime for the delayed display time, so the GPU
+ * moves every untracked contact between polls with no per-frame CPU pass.
+ */
+export function createIcons({ flightState, services, parts }) {
+  const { focusPassIsNeeded } = services.focus;
+  const scratchTime = new Cesium.JulianDate();
+  const scratchPosition = new Cesium.Cartesian3();
+  const scratchCull = new Cesium.Cartesian3();
+  const scratchScaleByDistance = new Cesium.NearFarScalar();
+  let normalScaleByDistance = null;
+  let cockpitScaleByDistance = null;
+
+  /** The delayed instant every untracked contact is drawn at. */
+  function _displayTime(result = scratchTime) {
+    return Cesium.JulianDate.addSeconds(
+      Cesium.JulianDate.now(result),
+      -RENDER_DELAY_SEC,
+      result,
+    );
+  }
+
+  function _displayTau() {
+    return flightState._icons.seconds(_displayTime());
+  }
+
+  /** Create the set and its primitive for one layer lifetime. */
+  function _createIcons(viewer) {
+    flightState._icons = createIconSet({ epoch: _displayTime() });
+    flightState._iconPrimitive = new IconSetPrimitive({
+      set: flightState._icons,
+      renderTime: () => _displayTime(flightState._scratchIconRenderTime),
+    });
+    viewer.scene.primitives.add(flightState._iconPrimitive);
+    return flightState._iconPrimitive;
+  }
+
+  /** Where a contact is drawn right now, or null when it has no row. */
+  function _iconPosition(icao24, result = new Cesium.Cartesian3()) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    return row < 0 ? null : set.position(row, _displayTau(), result);
+  }
+
+  /** The nose direction a contact is drawn with right now. */
+  function _iconCourse(icao24) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    return row < 0 ? null : set.course(row, _displayTau());
+  }
+
+  /** Whether the layer draws this contact's icon (not tracked, not model-owned). */
+  function _iconShown(icao24) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    return row >= 0 && set.shown(row);
+  }
+
+  /** The camera's horizon test, or null when there is no placed camera. */
+  function _occluder() {
+    const camera = flightState._viewer?.camera;
+    return camera?.positionWC ? horizonOccluder(camera) : null;
+  }
+
+  /** Whether a drawn row at `position` clears the camera's horizon, judged
+   *  exactly as the icon shader judges it. No camera, no horizon. */
+  function _aboveHorizon(row, position, occluder) {
+    return (
+      !occluder ||
+      occluder.isPointVisible(
+        flightState._icons.cullPoint(row, position, scratchCull),
+      )
+    );
+  }
+
+  /**
+   * Write the segment `_deadReckon` would follow from now on: interpolation
+   * between the bracketing fixes, the warm-up arc back from the oldest fix, or
+   * the coast arc past the newest. The displayed nose glides from where it is
+   * onto the new course at the fleet's slew cap; a hovering contact keeps its
+   * nose. The row expires when the regime would change.
+   * @param {string} icao24
+   * @param {{fromCourseDeg?: number|null}} [options] Nose to glide from when
+   *   the row's own segment is not what was on screen (tracking handoff).
+   */
+  function _planIcon(icao24, { fromCourseDeg } = {}) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    if (row < 0) return;
+    if (flightState._focusEvidenceIds.has(icao24)) return;
+    if (flightState._floorPinned.has(icao24)) return;
+    const history = flightState._positionHistory.get(icao24);
+    if (!history?.length) return;
+    const info = flightState.records.data.get(icao24);
+    const renderTime = _displayTime();
+    const tau = set.seconds(renderTime);
+    const seg = set.segments;
+    const shownCourse =
+      fromCourseDeg ??
+      (set.expires(row) === -Infinity ? null : set.course(row, tau));
+
+    const regime = parts.motion._motionRegime(history, info, renderTime);
+    let speed;
+    let expiresAt = Infinity;
+    if (regime.kind === 'between') {
+      const { a, b, span, trackFrom, trackTo, chordCourse } = regime;
+      speed = regime.speed;
+      const blend = chordCourse == null ? 0 : regime.blend;
+      const t0 = set.seconds(a.time);
+      if (span > 0) {
+        writeLerpSegment(seg, row, {
+          from: a.position,
+          to: b.position,
+          t0,
+          t1: set.seconds(b.time),
+          course0Deg:
+            trackFrom + blend * norm180((chordCourse ?? 0) - trackFrom),
+          courseSlopeDeg: norm180(trackTo - trackFrom) * (1 - blend),
+        });
+      } else {
+        writeHoldSegment(
+          seg,
+          row,
+          b.position,
+          trackTo + blend * norm180((chordCourse ?? 0) - trackTo),
+        );
+      }
+      expiresAt = set.seconds(b.time);
+    } else {
+      const { fix, heading } = regime;
+      speed = regime.speed;
+      const t0 = set.seconds(fix.time);
+      if (speed === 0) {
+        writeHoldSegment(seg, row, fix.position, heading);
+      } else {
+        writeArcSegment(seg, row, {
+          fix: fix.position,
+          t0,
+          minDt: regime.minDt,
+          maxDt: regime.maxDt,
+          speedMps: speed,
+          trackDeg: heading,
+          turnRateDps: regime.turnRateDps,
+        });
+      }
+      // A warm-up's arc ends at its fix; a coast's runs to its limit.
+      if (regime.maxDt === 0) expiresAt = t0;
+    }
+    // Below hover speed the nose holds what is on screen (or, for a new row,
+    // where this segment starts); above it, it glides on at the slew cap.
+    const hold = speed < COURSE_HOLD_SPEED_MPS;
+    if (hold || shownCourse != null) {
+      writeCourseGlide(
+        seg,
+        row,
+        shownCourse ?? segmentCourse(seg, row, tau),
+        tau,
+        hold ? 0 : courseSlewCapDps(speed, COURSE_MAX_DPS),
+      );
+    }
+    set.segmentWritten(row, expiresAt);
+  }
+
+  /** Re-plan every row whose regime ended before `tau`. */
+  function _replanExpired(tau) {
+    const set = flightState._icons;
+    const due = [];
+    for (let row = 0; row < set.count; row++)
+      if (set.expires(row) <= tau) due.push(set.idAt(row));
+    for (const icao24 of due) _planIcon(icao24);
+  }
+
+  /**
+   * Grounded contacts stand on the floor under where they are DRAWN, which the
+   * GPU cannot sample. While the floor lifts one, the CPU pins its row to a
+   * hold at the floored dead-reckoned position each tick (rewritten only when
+   * it moved); once nothing lifts it the row goes back to its planned segment.
+   */
+  function _floorGroundedIcons(renderTime, tau, nowMs, cameraPosition) {
+    const set = flightState._icons;
+    // Past FLOOR_NEAR_M a taxiing contact moves well under a pixel per tick,
+    // so far rows take turns: each refreshes every FLOOR_FAR_EVERY_TICKS. Their
+    // eases onto a lower floor advance per call, so they run that much slower
+    // out there too — sub-pixel at that range, and full rate once near.
+    const turn = flightState._floorTick++ % FLOOR_FAR_EVERY_TICKS;
+    const nearSq = FLOOR_NEAR_M * FLOOR_NEAR_M;
+    for (const icao24 of flightState._grounded) {
+      if (icao24 === flightState._trackedIcao) continue;
+      const row = set.row(icao24);
+      if (row < 0) continue;
+      if (
+        row % FLOOR_FAR_EVERY_TICKS !== turn &&
+        cameraPosition &&
+        Cesium.Cartesian3.distanceSquared(
+          cameraPosition,
+          set.position(row, tau, scratchPosition),
+        ) > nearSq
+      )
+        continue;
+      _floorIcon(icao24, renderTime, tau, nowMs);
+    }
+  }
+
+  /** One grounded contact's floor pass (see `_floorGroundedIcons`). */
+  function _floorIcon(icao24, renderTime, tau, nowMs) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    if (row < 0) return;
+    const info = flightState.records.data.get(icao24);
+    const raw = parts.motion._deadReckon(
+      icao24,
+      flightState._scratchFleetPos,
+      renderTime,
+    );
+    const rawCourse =
+      flightState._drCourseDeg ?? (info && info.true_track) ?? 0;
+    const hold = flightState._drCourseHold;
+    const speed = flightState._drSpeedMps ?? info?.velocity ?? NaN;
+    const display = parts.motion._floorGroundedDisplayPosition(
+      icao24,
+      info,
+      raw,
+      parts.rendering._modelOwnsVisual(icao24),
+      nowMs,
+    );
+    if (!display || display === raw) {
+      if (flightState._floorPinned.delete(icao24))
+        _planIcon(icao24, { fromCourseDeg: set.course(row, tau) });
+      return;
+    }
+    const planned = set.expires(row) !== -Infinity;
+    const prev = planned ? set.course(row, tau) : null;
+    // The pin holds the position; the GPU glides the course onto the target,
+    // so the rate stays exact however seldom the pin is rewritten.
+    const target = hold && prev != null ? prev : rawCourse;
+    if (
+      flightState._floorPinned.has(icao24) &&
+      Cesium.Cartesian3.distanceSquared(
+        display,
+        set.position(row, tau, scratchPosition),
+      ) <= PIN_MOVE_SQ_M &&
+      Math.abs(norm180(target - segmentTargetCourse(set.segments, row, tau))) <=
+        PIN_TURN_DEG
+    )
+      return;
+    flightState._floorPinned.add(icao24);
+    writeHoldSegment(set.segments, row, display, target);
+    if (prev != null)
+      writeCourseGlide(
+        set.segments,
+        row,
+        prev,
+        tau,
+        courseSlewCapDps(speed, COURSE_MAX_DPS),
+      );
+    set.segmentWritten(row);
+  }
+
+  /**
+   * Advance focus de-emphasis for every drawn row (and every row a fleet model
+   * draws for, whose alpha reads it), only while a focus target exists or some
+   * row is still relaxing back to full emphasis.
+   */
+  function _focusIcons(tau, scene, camera, nowMs, target) {
+    if (!focusPassIsNeeded(target, flightState._iconFocusActive)) return;
+    const { advanceProjectedSpriteFocus, nearFarScalarValueAtDistance } =
+      services.focus;
+    const set = flightState._icons;
+    let active = 0;
+    for (let row = 0; row < set.count; row++) {
+      if (!set.shown(row) && !flightState._models.has(set.idAt(row))) continue;
+      const position = set.position(row, tau, scratchPosition);
+      const distanceScale = nearFarScalarValueAtDistance(
+        set.scaleByDistance(row, scratchScaleByDistance),
+        Cesium.Cartesian3.distance(camera.positionWC, position),
+      );
+      const half = set.scale(row) * distanceScale * 0.5;
+      const focus = advanceProjectedSpriteFocus(
+        set.metaAt(row),
+        position,
+        scene,
+        camera,
+        nowMs,
+        target,
+        undefined,
+        set.width(row) * half,
+        set.height(row) * half,
+      );
+      set.setFocus(row, focus.factor);
+      if (focus.active || focus.transitioning) active++;
+    }
+    flightState._iconFocusActive = active;
+  }
+
+  /** Image, size, scale, tint and freshness for one row under the current
+   *  normal/cockpit contract. Motion and rotation stay with the segment. */
+  function _applyIconPresentation(icao24) {
+    const set = flightState._icons;
+    const row = set.row(icao24);
+    if (row < 0) return;
+    const info = flightState.records.data.get(icao24);
+    const tracked = icao24 === flightState._trackedIcao;
+    const cockpitDot =
+      flightState._cockpitContactMode &&
+      !tracked &&
+      !flightState._cockpitNearContacts.has(icao24);
+    if (cockpitDot) {
+      const dot = iconAtlas.slot(cockpitContactDotImage(), COCKPIT_DOT_PX);
+      set.setImage(row, dot, dot);
+      set.setSize(row, COCKPIT_CONTACT_SIZE_PX, COCKPIT_CONTACT_SIZE_PX);
+      set.setScale(row, 1);
+      cockpitScaleByDistance ??=
+        parts.rendering._cockpitBillboardScaleByDistance();
+      set.setScaleByDistance(row, cockpitScaleByDistance);
+      set.setColor(row, parts.rendering._cockpitContactColor(icao24, info));
+      set.setFlag(row, ICON_ROTATES, false);
+    } else {
+      set.setImage(
+        row,
+        iconAtlas.slot(
+          aircraftIcon(parts.rendering._iconKind(icao24, info?.klass)),
+          FLEET_ICON_PX,
+        ),
+        iconAtlas.slot(
+          aircraftIcon(
+            parts.rendering._iconKind(icao24, info?.klass),
+            TRACKED_ICON_PX,
+          ),
+          TRACKED_ICON_PX,
+        ),
+      );
+      const size = tracked ? 24 : 20;
+      set.setSize(row, size, size);
+      set.setScale(
+        row,
+        parts.rendering._fleetBillboardScale(icao24, info?.klass),
+      );
+      normalScaleByDistance ??=
+        parts.rendering._normalBillboardScaleByDistance();
+      set.setScaleByDistance(row, normalScaleByDistance);
+      set.setColor(row, parts.rendering._fleetBillboardColor(icao24, info));
+      set.setFlag(row, ICON_ROTATES, true);
+    }
+    set.setFlag(row, ICON_RECEDES, true);
+    set.setFlag(
+      row,
+      ICON_CULL_LIFT,
+      Number.isFinite(info?.renderAltitudeM) && info.renderAltitudeM < 10,
+    );
+    set.setAlpha(row, flightState.records.missingPolls.get(icao24) ? 0.45 : 1);
+  }
+
+  /** Add a row for a new contact, hidden while it is the tracked one. */
+  function _addIcon(icao24) {
+    const set = flightState._icons;
+    const row = set.add(icao24, { layer: 'flights', id: icao24 });
+    _applyIconPresentation(icao24);
+    _settleIcon(icao24);
+    set.setShown(row, icao24 !== flightState._trackedIcao);
+    return row;
+  }
+
+  /**
+   * Plan a row afresh, dropping any floor pin (a pin stops at the last floor
+   * pass, which skips a tracked contact), and let a dimmed row relax. A grounded contact goes straight onto
+   * the floor under where it is drawn, not its fix's floor until the next fleet
+   * tick raises it.
+   * @param {string} icao24
+   * @param {{fromCourseDeg?: number}} [options] The course on screen to glide from.
+   */
+  function _settleIcon(icao24, options) {
+    const set = flightState._icons;
+    flightState._floorPinned.delete(icao24);
+    // A row that sat out the focus pass (tracked) may come back dimmed after
+    // the pass went idle; count it so the pass runs and relaxes it.
+    if (set.focus(set.row(icao24)) < 1) flightState._iconFocusActive += 1;
+    _planIcon(icao24, options);
+    if (flightState._grounded.has(icao24)) {
+      const renderTime = _displayTime();
+      _floorIcon(icao24, renderTime, set.seconds(renderTime), Date.now());
+    }
+  }
+
+  /** Drop a contact and everything the layer keeps for it. */
+  function _forgetContact(icao24) {
+    flightState._icons?.remove(icao24);
+    parts.rendering._releaseModel(icao24);
+    flightState.records.forget(icao24);
+    flightState._positionHistory.delete(icao24);
+    flightState._displayCourse.delete(icao24);
+    flightState._groundSnap.forget(icao24);
+    flightState._displayFloorState.delete(icao24);
+    flightState._grounded.delete(icao24);
+    flightState._floorPinned.delete(icao24);
+  }
+
+  /** Icon ids, so ray samples never land on an aircraft instead of the ground. */
+  function _iconIds() {
+    const set = flightState._icons;
+    const ids = new Array(set?.count ?? 0);
+    for (let row = 0; row < ids.length; row++) ids[row] = set.idAt(row);
+    return ids;
+  }
+
+  return {
+    _displayTime,
+    _displayTau,
+    _createIcons,
+    _iconPosition,
+    _iconCourse,
+    _iconShown,
+    _occluder,
+    _aboveHorizon,
+    _planIcon,
+    _settleIcon,
+    _replanExpired,
+    _floorGroundedIcons,
+    _focusIcons,
+    _applyIconPresentation,
+    _addIcon,
+    _forgetContact,
+    _iconIds,
+  };
+}
@@ -0,0 +1,120 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import * as Cesium from 'cesium';
+import { createFlightState } from './state.js';
+import { createIcons } from './icons.js';
+import { createIconSet } from '../../data/iconSet.js';
+import { writeHoldSegment } from '../../data/iconSegment.js';
+
+function services(focus = {}) {
+  return {
+    focus: { focusPassIsNeeded: () => true, ...focus },
+    groundSnap: { createGroundSnap: () => ({ clear() {}, forget() {} }) },
+  };
+}
+
+function setup({ focus, motion = {}, rendering = {} } = {}) {
+  const svc = services(focus);
+  const flightState = createFlightState({ services: svc });
+  flightState._icons = createIconSet();
+  const parts = {
+    motion,
+    rendering: { _modelOwnsVisual: () => false, ...rendering },
+  };
+  const icons = createIcons({ flightState, services: svc, parts });
+  return { flightState, icons, set: flightState._icons };
+}
+
+function hold(set, id, position, course = 0) {
+  const row = set.add(id, { layer: 'flights', id });
+  writeHoldSegment(set.segments, row, position, course);
+  set.segmentWritten(row);
+  return row;
+}
+
+const at = (lon, h = 1000) => Cesium.Cartesian3.fromDegrees(lon, 30, h);
+
+test('focus advances for drawn rows and for rows a fleet model draws for', () => {
+  const advanced = [];
+  const { flightState, icons, set } = setup({
+    focus: {
+      nearFarScalarValueAtDistance: () => 1,
+      advanceProjectedSpriteFocus(meta) {
+        advanced.push(meta.id);
+        return { factor: 0.4, active: true };
+      },
+    },
+  });
+  set.setShown(hold(set, 'drawn', at(0)), true);
+  const modeled = hold(set, 'modeled', at(0.1));
+  hold(set, 'hidden', at(0.2));
+  flightState._models.set('modeled', {});
+
+  icons._focusIcons(0, {}, { positionWC: at(0, 50_000) }, 0, {});
+  assert.deepEqual(advanced, ['drawn', 'modeled']);
+  assert.ok(
+    Math.abs(set.focus(modeled) - 0.4) < 1e-6,
+    "the model's alpha reads it",
+  );
+  assert.equal(flightState._iconFocusActive, 2);
+});
+
+test('settling a pinned grounded contact re-floors it where it is now, nose kept', () => {
+  const taxied = at(0.01, 100);
+  const floored = at(0.01, 131.5);
+  const { flightState, icons, set } = setup({
+    motion: {
+      _motionRegime: () => ({
+        kind: 'fix',
+        fix: { position: taxied, time: Cesium.JulianDate.now() },
+        speed: 0,
+        heading: 200,
+        turnRateDps: 0,
+        minDt: -60,
+        maxDt: 60,
+      }),
+      _deadReckon(icao24, result) {
+        flightState._drCourseDeg = 200;
+        flightState._drSpeedMps = 0;
+        flightState._drCourseHold = true;
+        return Cesium.Cartesian3.clone(taxied, result);
+      },
+      _floorGroundedDisplayPosition: () => floored,
+    },
+  });
+  // Pinned before it was tracked, 1 km back, facing 10°.
+  const row = hold(set, 'g', at(0, 131.5), 10);
+  flightState._floorPinned.add('g');
+  flightState._grounded.add('g');
+  flightState.records.data.set('g', { onGround: true });
+  flightState._positionHistory.set('g', [{}]);
+
+  icons._settleIcon('g', { fromCourseDeg: 123 });
+  const tau = icons._displayTau();
+  assert.ok(Cesium.Cartesian3.distance(set.position(row, tau), floored) < 0.01);
+  assert.ok(Math.abs(set.course(row, tau) - 123) < 1e-3, 'tracked nose kept');
+  assert.ok(flightState._floorPinned.has('g'), 'pinned on the new floor');
+});
+
+test('a contact that comes back dimmed re-arms the idle focus pass', () => {
+  const advanced = [];
+  const { flightState, icons, set } = setup({
+    focus: {
+      focusPassIsNeeded: (target, active) => target != null || active > 0,
+      nearFarScalarValueAtDistance: () => 1,
+      advanceProjectedSpriteFocus(meta) {
+        advanced.push(meta.id);
+        return { factor: 1, active: false, transitioning: false };
+      },
+    },
+    motion: { _motionRegime: () => null },
+  });
+  const row = hold(set, 'was-tracked', at(0));
+  set.setFocus(row, 0.2);
+  flightState._iconFocusActive = 0;
+  icons._settleIcon('was-tracked');
+  set.setShown(row, true);
+  icons._focusIcons(0, {}, { positionWC: at(0, 50_000) }, 0, null);
+  assert.deepEqual(advanced, ['was-tracked']);
+  assert.equal(set.focus(row), 1);
+});
@@ -1,6 +1,7 @@
 import { createFlightSnapshotRenderer } from './snapshotRenderer.js';
 import { createFlightState } from './state.js';
 import { createRendering } from './rendering.js';
+import { createIcons } from './icons.js';
 import { createMotion } from './motion.js';
 import { createTracking } from './tracking.js';
 import { createController } from './controller.js';
@@ -21,6 +22,7 @@ export function createCivilFlightLayer({
  const layer = {};
  const context = { flightState, services, parts, layer, resolveAsset };
  parts.rendering = createRendering(context);
+  parts.icons = createIcons(context);
  parts.motion = createMotion(context);
  parts.tracking = createTracking(context);
  parts.controller = createController(context);
@@ -38,6 +40,7 @@ export function createCivilFlightLayer({
    rendering: parts.rendering,
    tracking: parts.tracking,
    motion: parts.motion,
+    icons: parts.icons,
    enrichment: parts.enrichment,
    queries: parts.queries,
  });
@@ -34,7 +34,7 @@ export function createLifecycle({

    /**
     * Initialize the flights layer.
-     * Creates the BillboardCollection, resets all state, and installs the
+     * Creates the icon set and its primitive, resets all state, and installs the
     * click-to-track handler on the scene canvas.
     * @param {Cesium.Viewer} viewer - The CesiumJS viewer instance.
     */
@@ -48,9 +48,7 @@ export function createLifecycle({
      clearFocusTarget('flights');
      flightState._focusEvidenceIds.clear();
      flightState._viewer = viewer;
-      flightState._billboardCollection = new Cesium.BillboardCollection();
-      viewer.scene.primitives.add(flightState._billboardCollection);
-      registerSpriteCollection('flights', flightState._billboardCollection);
+      registerSpriteCollection('flights', parts.icons._createIcons(viewer));
      flightState._modelCollection = new Cesium.PrimitiveCollection();
      viewer.scene.primitives.add(flightState._modelCollection);
      // Warm the glTF cache so the tracked plane's model instantiates instantly when first needed
@@ -78,8 +76,9 @@ export function createLifecycle({
            /* tracked plane just stays a billboard a beat longer */
          });
      }
-      flightState._billboards = new Map();
-      flightState._cullPositions.clear();
+      flightState._grounded.clear();
+      flightState._floorPinned.clear();
+      flightState._iconFocusActive = 0;
      flightState._detectionObjects = new Map();
      flightState.records.data = new Map();
      flightState._positionHistory = new Map();
@@ -126,16 +125,15 @@ export function createLifecycle({

      restoreSpriteOrder(viewer);

-      console.log('[Data:Flights] Initialized with billboard icons');
+      console.log('[Data:Flights] Initialized with GPU icons');
    },

    /**
-     * Show the billboard collection and re-install the click handler.
+     * Show the icons and re-install the click handler.
     * @param {Cesium.Viewer} viewer
     */
    enable(viewer) {
-      if (flightState._billboardCollection)
-        flightState._billboardCollection.show = true;
+      if (flightState._icons) flightState._icons.show = true;
      holdContinuousRender('flights'); // per-frame animator (perf wave 2)
      if (flightState._modelCollection)
        flightState._modelCollection.show = true;
@@ -156,11 +154,10 @@ export function createLifecycle({
          });
      }
      parts.tracking._installClickHandler(viewer);
-      registerPickOwner('flights', (pickedId) =>
-        flightState._billboards.has(pickedId),
+      registerPickOwner(
+        'flights',
+        (pickedId) => flightState._icons?.has(pickedId) === true,
      );
-      // Force a fresh rotation pass on the first tick after re-enable
-      flightState._lastCamPoseSig = '';
      if (!flightState._preRenderRemove && viewer?.scene) {
        flightState._preRenderRemove = viewer.scene.preRender.addEventListener(
          parts.rendering._fleetTick,
@@ -173,18 +170,11 @@ export function createLifecycle({
          );
      }
      if (!flightState._moveEndRemove && viewer?.camera) {
-        // Arrival polish (field test 2026-07-03: "planes look weird when you first
-        // come to them"): when a camera move SETTLES (voice fly-to, fast pan
-        // release), force a full rotation pass on the very next frame. The
-        // pose-signature gate alone can eat the settle — the final easing frames
-        // of a flight land inside one quantization bucket (10 m / 0.06°), leaving
-        // every icon wearing its last mid-flight rotation for up to
-        // ROTATION_REFRESH_MS. Zeroing the tick throttle too means the pass runs
-        // on the next preRender, not up to FLEET_DR_INTERVAL_MS later. Cost: one
-        // extra rotation pass per completed camera gesture — nothing per-frame.
+        // A settled camera move (voice fly-to, fast pan release) runs the fleet
+        // pass on the very next preRender rather than up to FLEET_DR_INTERVAL_MS
+        // later, so the model handoff and focus land with the camera.
        flightState._moveEndRemove = viewer.camera.moveEnd.addEventListener(
          () => {
-            flightState._lastCamPoseSig = '';
            flightState._lastFleetTickMs = 0;
          },
        );
@@ -193,15 +183,14 @@ export function createLifecycle({
    },

    /**
-     * Hide all flight billboards and tear down click/keyboard handlers.
+     * Hide all flight icons and tear down click/keyboard handlers.
     * Also clears any active flight tracking so the camera is released.
     * @param {Cesium.Viewer} viewer
     */
    disable(viewer) {
      parts.controller._abortActiveUpdates();
      parts.tracking._cancelPendingTrackingRestore();
-      if (flightState._billboardCollection)
-        flightState._billboardCollection.show = false;
+      if (flightState._icons) flightState._icons.show = false;
      releaseContinuousRender('flights');
      parts.rendering._releaseModels();
      if (flightState._modelCollection)
@@ -282,10 +271,12 @@ export function createLifecycle({
        flightState._moveEndRemove = null;
      }
      parts.rendering._releaseModels();
-      if (flightState._billboardCollection) {
-        viewer.scene.primitives.remove(flightState._billboardCollection);
-        flightState._billboardCollection = null;
+      if (flightState._iconPrimitive) {
+        viewer.scene.primitives.remove(flightState._iconPrimitive); // removing destroys it
+        flightState._iconPrimitive = null;
      }
+      flightState._icons?.clear();
+      flightState._icons = null;
      if (flightState._modelCollection) {
        viewer.scene.primitives.remove(flightState._modelCollection); // removing destroys it + its models
        flightState._modelCollection = null;
@@ -302,8 +293,9 @@ export function createLifecycle({
        flightState._preloadModel = null;
      }
      flightState._planeModelLoaded = false;
-      flightState._billboards.clear();
-      flightState._cullPositions.clear();
+      flightState._grounded.clear();
+      flightState._floorPinned.clear();
+      flightState._iconFocusActive = 0;
      flightState._detectionObjects.clear();
      flightState.records.data.clear();
      flightState._positionHistory.clear();
@@ -35,10 +35,23 @@ import {
  DISPLAY_CORRIDOR_CELL_BUDGET,
  DISPLAY_CORRIDOR_FAIR_SHARE,
 } from './policy.js';
-import { billboardState, setBillboard } from '../../data/billboardMirror.js';
 import { modelState } from '../../data/modelMirror.js';
 import { readEntityRecord } from '../../data/entityRecords.js';

+/** A fix's own ground speed, else the record's. */
+function fixSpeedMps(fix, info) {
+  return Number.isFinite(fix.velocity)
+    ? fix.velocity
+    : (info && info.velocity) || 0;
+}
+
+/** A fix's own track, else the record's. */
+function fixTrackDeg(fix, info) {
+  return Number.isFinite(fix.track)
+    ? fix.track
+    : (info && info.true_track) || 0;
+}
+
 export function createMotion({
  flightState,
  services,
@@ -66,6 +79,23 @@ export function createMotion({
  // Fixes leave the cache with their history; corrected positions invalidate
  // the local frame even when the existing Cartesian is mutated in place.
  const fixFrames = new WeakMap();
+  /** `_motionRegime`'s reused result. */
+  const regime = {
+    kind: 'fix',
+    a: null,
+    b: null,
+    span: 0,
+    speed: 0,
+    trackFrom: 0,
+    trackTo: 0,
+    chordCourse: null,
+    blend: 0,
+    fix: null,
+    heading: 0,
+    turnRateDps: 0,
+    minDt: 0,
+    maxDt: 0,
+  };

  // Round 5: the old `_warmGroundedAircraftSurfaceCache` (global exact-5-decimal
  // warm for every grounded contact on Earth) is GONE. Parked-aircraft GPS
@@ -81,7 +111,7 @@ export function createMotion({
   * coasting on its final meta — if that fix predated the floor warm, it sat
   * frozen underground forever. Runs once per poll over the (bounded) flight
   * map; touches only grounded, feed-absent, demonstrably-below-floor
-   * contacts, and patches the stored fix + billboard in place (zero-velocity
+   * contacts, and patches the stored fix + icon in place (zero-velocity
   * DR renders the patched fix verbatim).
   * @param {Set<string>} currentIcaos - Contacts present in THIS poll (already
   *   floored by the live path — skipped here).
@@ -101,7 +131,6 @@ export function createMotion({
      )
        continue;
      info.renderAltitudeM = lifted;
-      flightState._cullPositions.delete(icao24); // above the ellipsoid now (or floors say otherwise next poll)
      const position = Cesium.Cartesian3.fromDegrees(
        info.rawLon,
        info.rawLat,
@@ -111,8 +140,9 @@ export function createMotion({
      const newest = history?.[history.length - 1];
      if (newest)
        newest.position = Cesium.Cartesian3.clone(position, newest.position);
-      const bb = flightState._billboards.get(icao24);
-      if (bb) setBillboard(bb, 'position', position);
+      // Above the ellipsoid now (or floors say otherwise next poll).
+      parts.icons._applyIconPresentation(icao24);
+      parts.icons._planIcon(icao24);
    }
  }

@@ -134,9 +164,7 @@ export function createMotion({
  function _deadReckon(icao24, result, sampledRenderTime) {
    const info = flightState.records.data.get(icao24);
    if (FOCUS_EVIDENCE_DEV && flightState._focusEvidenceIds.has(icao24)) {
-      const position = billboardState(
-        flightState._billboards.get(icao24),
-      )?.position;
+      const position = parts.icons._iconPosition(icao24);
      flightState._drCourseDeg = info?.true_track || 0;
      flightState._drSpeedMps = info?.velocity || 0;
      flightState._drCourseHold =
@@ -166,100 +194,113 @@ export function createMotion({
        flightState._scratchRenderTime,
      );

-    // Bracketing pair: interpolate — no extrapolation error, no snap-back.
+    const regime = _motionRegime(history, info, renderTime);
+    if (regime.kind === 'between') {
+      const { a, b, span } = regime;
+      const t =
+        span > 0
+          ? Cesium.JulianDate.secondsDifference(renderTime, a.time) / span
+          : 1.0;
+      const trackCourse = lerpAngleDeg(regime.trackFrom, regime.trackTo, t);
+      flightState._drCourseDeg =
+        regime.chordCourse != null
+          ? lerpAngleDeg(trackCourse, regime.chordCourse, regime.blend)
+          : trackCourse;
+      flightState._drSpeedMps = regime.speed;
+      flightState._drCourseHold = regime.speed < COURSE_HOLD_SPEED_MPS;
+      flightState._drExtrapolating = false;
+      return Cesium.Cartesian3.lerp(a.position, b.position, t, out);
+    }
+    const dt = Cesium.Math.clamp(
+      Cesium.JulianDate.secondsDifference(renderTime, regime.fix.time),
+      regime.minDt,
+      regime.maxDt,
+    );
+    return _extrapolateFix(regime.fix, info, dt, out, regime.turnRateDps);
+  }
+
+  /**
+   * Which motion a contact's history gives at `renderTime` — the one choice
+   * `_deadReckon` (CPU) and the icon planner (GPU segment) both draw from.
+   *
+   * - `between`: interpolate the bracketing pair `a`→`b`, no extrapolation
+   *   error and no snap-back. The course of the DISPLAYED motion blends the
+   *   time-interpolated reported track toward the chord by `blend`: the chord
+   *   is only trustworthy when the segment covers real ground (at hover its
+   *   direction is GPS jitter; on a slow tight turn it STEPS the whole
+   *   per-segment turn at each boundary), and helicopters never use it
+   *   (rotorcraft chords are noise-dominated at their typical speeds).
+   * - `fix`: extrapolate `fix` by the elapsed time clamped to [minDt, maxDt].
+   *   Warm-up (renderTime predates ALL history: freshly seen or just tracked,
+   *   before RENDER_DELAY_SEC of history exists) runs the OLDEST fix BACKWARD,
+   *   preserving the 30s-behind invariant, so as history fills the icon glides
+   *   FORWARD into interpolation with no freeze and no backward snap (holding
+   *   the oldest fix froze the icon; extrapolating the newest to wall-clock
+   *   made it jump back a poll interval when interpolation took over).
+   *   Otherwise the newest fix coasts. OpenSky can still be receiving fresh
+   *   contact messages for that aircraft; freezing 60 s after the position
+   *   produced a stop → catch-up → stop cadence, so it coasts through the latest
+   *   real contact plus a bounded grace, with an absolute cap so a stale cached
+   *   feed cannot drift forever.
+   *
+   * The returned object is a reused scratch: read it before the next call.
+   * @param {Array<object>} history Non-empty, oldest first.
+   * @param {object|undefined} info The contact's record.
+   * @param {Cesium.JulianDate} renderTime
+   */
+  function _motionRegime(history, info, renderTime) {
    for (let i = history.length - 1; i >= 1; i--) {
      const a = history[i - 1];
      const b = history[i];
      if (
-        Cesium.JulianDate.lessThanOrEquals(a.time, renderTime) &&
-        Cesium.JulianDate.lessThanOrEquals(renderTime, b.time)
-      ) {
-        const span = Cesium.JulianDate.secondsDifference(b.time, a.time);
-        const t =
-          span > 0
-            ? Cesium.JulianDate.secondsDifference(renderTime, a.time) / span
-            : 1.0;
-        // Course of the DISPLAYED motion. The chord is only trustworthy when the
-        // segment covers real ground (at hover its direction is GPS jitter; on a
-        // slow tight turn it STEPS the whole per-segment turn at each boundary),
-        // so it is blended against the reported per-fix track by displayed
-        // ground speed — and the track is TIME-INTERPOLATED between the fixes so
-        // a slow turner's nose advances continuously through the segment instead
-        // of snapping once per poll. Helicopters always use the reported track
-        // (rotorcraft chords are noise-dominated at their typical speeds).
-        const chordLenM = Cesium.Cartesian3.distance(a.position, b.position);
-        const segSpeed =
-          span > 0 ? chordLenM / span : (info && info.velocity) || 0;
-        const fallbackTrack = (info && info.true_track) || 0;
-        const trackFrom = Number.isFinite(a.track) ? a.track : fallbackTrack;
-        const trackTo = Number.isFinite(b.track) ? b.track : trackFrom;
-        const trackCourse = lerpAngleDeg(trackFrom, trackTo, t);
-        const w = info && info.klass === 'helicopter' ? 0 : speedRamp(segSpeed);
-        const chordCourse =
-          w > 0 ? courseBetweenCartesians(a.position, b.position) : null;
-        flightState._drCourseDeg =
-          chordCourse != null
-            ? lerpAngleDeg(trackCourse, chordCourse, w)
-            : trackCourse;
-        flightState._drSpeedMps = segSpeed;
-        flightState._drCourseHold = segSpeed < COURSE_HOLD_SPEED_MPS;
-        flightState._drExtrapolating = false;
-        return Cesium.Cartesian3.lerp(a.position, b.position, t, out);
-      }
+        !Cesium.JulianDate.lessThanOrEquals(a.time, renderTime) ||
+        !Cesium.JulianDate.lessThanOrEquals(renderTime, b.time)
+      )
+        continue;
+      const span = Cesium.JulianDate.secondsDifference(b.time, a.time);
+      const chordLenM = Cesium.Cartesian3.distance(a.position, b.position);
+      const speed = span > 0 ? chordLenM / span : (info && info.velocity) || 0;
+      const fallbackTrack = (info && info.true_track) || 0;
+      const trackFrom = Number.isFinite(a.track) ? a.track : fallbackTrack;
+      const blend = info && info.klass === 'helicopter' ? 0 : speedRamp(speed);
+      regime.kind = 'between';
+      regime.a = a;
+      regime.b = b;
+      regime.span = span;
+      regime.speed = speed;
+      regime.trackFrom = trackFrom;
+      regime.trackTo = Number.isFinite(b.track) ? b.track : trackFrom;
+      regime.chordCourse =
+        blend > 0 ? courseBetweenCartesians(a.position, b.position) : null;
+      regime.blend = blend;
+      return regime;
    }
-
    const newest = history[history.length - 1];
-    const elapsedSec = Cesium.JulianDate.secondsDifference(
-      renderTime,
-      newest.time,
-    );
-    if (elapsedSec <= 0) {
-      // Warm-up: renderTime predates ALL history (freshly seen / just-started-tracking
-      // aircraft, before RENDER_DELAY_SEC of history has accumulated, so no bracketing
-      // pair exists yet). Render at the DELAYED renderTime — preserving the 30s-behind
-      // invariant — by extrapolating the OLDEST fix BACKWARD to renderTime. As history
-      // fills, renderTime advances toward the first fix and the icon glides FORWARD into
-      // the bracketing interpolation above with NO freeze and NO backward snap. (Holding
-      // the oldest fix froze the icon; extrapolating the NEWEST fix to wall-clock now made
-      // the icon jump back ~one poll interval the instant interpolation took over.)
-      const oldest = history[0];
-      const lookbackSec = Cesium.JulianDate.secondsDifference(
-        oldest.time,
-        renderTime,
-      ); // ≥ 0
-      return _extrapolateFix(
-        oldest,
-        info,
-        -Math.min(lookbackSec, 60),
-        out,
-        (info && info.turnRateDps) || 0,
-      );
-    }
-
-    // Newest POSITION is older than renderTime. OpenSky can still be receiving
-    // fresh contact/kinematic messages for that aircraft; freezing at a hard
-    // 60 s-after-position boundary produced the visible stop → catch-up → stop
-    // cadence. Coast through the latest real contact plus a bounded grace
-    // window, with an absolute cap so a stale cached feed cannot drift forever.
-    const coastLimitSec = staleCoastLimitSeconds({
-      // `epochMs` is captured once when the poll is normalized. Avoid allocating
-      // a Date per aircraft on every 12 Hz fleet tick.
-      fixEpochMs: Number.isFinite(newest.epochMs)
-        ? newest.epochMs
-        : Cesium.JulianDate.toDate(newest.time).getTime(),
-      lastContactEpochMs: info?.lastContactEpochMs,
-      // Permit one minute of contact grace but cap any cached-feed drift at
-      // five minutes. Source backoff is exposed separately as a STALE cue.
-      minimumSec: 60,
-      maximumSec: 300,
-    });
-    return _extrapolateFix(
-      newest,
-      info,
-      Math.min(elapsedSec, coastLimitSec),
-      out,
-      (info && info.turnRateDps) || 0,
-    );
+    const warming = Cesium.JulianDate.lessThan(renderTime, history[0].time);
+    regime.kind = 'fix';
+    regime.fix = warming ? history[0] : newest;
+    regime.speed = fixSpeedMps(regime.fix, info);
+    regime.heading = fixTrackDeg(regime.fix, info);
+    regime.turnRateDps = (info && info.turnRateDps) || 0;
+    regime.minDt = -60;
+    // A warm-up ends when real time reaches the oldest fix; a single fix keeps
+    // coasting forward on the same arc.
+    regime.maxDt =
+      warming && history.length > 1
+        ? 0
+        : staleCoastLimitSeconds({
+            // `epochMs` is captured once when the poll is normalized. Avoid
+            // allocating a Date per aircraft on every 12 Hz fleet tick.
+            fixEpochMs: Number.isFinite(newest.epochMs)
+              ? newest.epochMs
+              : Cesium.JulianDate.toDate(newest.time).getTime(),
+            lastContactEpochMs: info?.lastContactEpochMs,
+            // Permit one minute of contact grace but cap any cached-feed drift
+            // at five minutes. Source backoff is exposed separately as a STALE cue.
+            minimumSec: 60,
+            maximumSec: 300,
+          });
+    return regime;
  }

  /**
@@ -274,12 +315,8 @@ export function createMotion({
   */

  function _extrapolateFix(fix, info, dt, out, turnRateDps = 0) {
-    const speed = Number.isFinite(fix.velocity)
-      ? fix.velocity
-      : (info && info.velocity) || 0;
-    const heading = Number.isFinite(fix.track)
-      ? fix.track
-      : (info && info.true_track) || 0;
+    const speed = fixSpeedMps(fix, info);
+    const heading = fixTrackDeg(fix, info);
    flightState._drSpeedMps = speed;
    flightState._drCourseHold = speed < COURSE_HOLD_SPEED_MPS;
    flightState._drExtrapolating = true;
@@ -1114,6 +1151,7 @@ export function createMotion({
  return {
    _refloorStaleGroundedContacts,
    _deadReckon,
+    _motionRegime,
    _extrapolateFix,
    _isTrackWarmingUp,
    _trackedFocusSizePx,
@@ -59,7 +59,8 @@ test('flight state owns distinct mutable records, scratch objects and floor samp
  for (const key of [
    'records',
    'feed',
-    '_billboards',
+    '_grounded',
+    '_floorPinned',
    '_positionHistory',
    '_displayFloorState',
    '_groundSnap',
@@ -207,6 +207,14 @@ export const COURSE_MAX_DPS = 60;

 export const COURSE_SLEW_DT_MAX_SEC = 0.25;

+/** Grounded contacts this close to the camera are floored every fleet tick. */
+
+export const FLOOR_NEAR_M = 50_000;
+
+/** Farther grounded contacts are floored once per this many fleet ticks (~1 s). */
+
+export const FLOOR_FAR_EVERY_TICKS = 12;
+
 // ---------------------------------------------------------------------------
 // adsbdb enrichment (best-effort, fail-silent). Bounded fan-out: max 4
 // concurrent requests, dispatches dripped ≥ENRICH_DISPATCH_GAP_MS apart
@@ -16,7 +16,6 @@ import {
  FLEET_DR_INTERVAL_MS,
 } from './policy.js';
 import { emergencyBroadcastPhrase } from '../../data/aircraftEmergency.js';
-import { billboardState, setBillboard } from '../../data/billboardMirror.js';
 import { modelState } from '../../data/modelMirror.js';

 export function createQueries({
@@ -99,7 +98,7 @@ export function createQueries({
   * airframe itself and cannot go stale the way a leg can.
   *
   * This is a DISPLAY string only. Identity everywhere in this layer is `icao24`
-   * (the `_billboards`/`_flightData` key, the `sourceId` detection declutter hashes,
+   * (the `_icons`/`_flightData` key, the `sourceId` detection declutter hashes,
   * the `id` that trackById/Context cohorts resolve) — never the label.
   * @param {string} icao24 - ICAO 24-bit transponder address (the identity key).
   * @param {Object|null|undefined} info - `_flightData` record for this aircraft.
@@ -134,10 +133,8 @@ export function createQueries({
    // every visual consumer reads the floored per-frame cache instead (see
    // `_trackedDisplayPosition`). If that ever changes, floor this path too.
    const info = flightState.records.data.get(icao24);
-    const bb = flightState._billboards.get(icao24);
    const basePos =
-      parts.motion._deadReckon(icao24) ||
-      (bb ? billboardState(bb).position : null);
+      parts.motion._deadReckon(icao24) || parts.icons._iconPosition(icao24);
    if (!basePos) return null;
    const displayed = displayedKinematics({
      derivedSpeedMps: flightState._drSpeedMps,
@@ -334,14 +331,8 @@ export function createQueries({
        if (!flightState._models3dEnabled) {
          parts.rendering._releaseModels();
          parts.tracking._syncTracked2dRotation();
-          // Restore fleet billboards (the horizon-cull pass re-asserts next tick), but NEVER the
-          // tracked plane's own fleet billboard — its tracked entity is the visual, so re-showing it
-          // here would double-image the tracked plane when 3D is turned off mid-track.
-          if (flightState._billboardCollection)
-            for (const [icao, bb] of flightState._billboards) {
-              if (icao !== flightState._trackedIcao)
-                setBillboard(bb, 'show', true);
-            }
+          // (Releasing the models handed each fleet contact back to its icon, never
+          // the tracked plane's own — its tracked entity is the visual.)
        }
      }
      if (
@@ -424,42 +415,34 @@ export function createQueries({
     * @returns {Array<{position: Cesium.Cartesian3, id: string, type: string, skipLabel: boolean}>}
     */
    getDetectableObjects(options = {}) {
-      if (
-        !flightState._billboardCollection ||
-        !flightState._billboardCollection.show
-      )
-        return [];
-      // Compute a stride that evenly samples the billboard map.
+      const icons = flightState._icons;
+      if (!icons || !icons.show) return [];
+      // Compute a stride that evenly samples the icon rows.
      // seed shifts the starting offset so successive calls can sample
-      // different aircraft without shuffling the underlying Map order.
+      // different aircraft without reordering the rows.
      const maxCount = Number.isFinite(options.maxCount)
        ? Math.max(1, Math.floor(options.maxCount))
-        : flightState._billboards.size;
+        : icons.count;
      const seed = Number.isFinite(options.seed) ? Math.floor(options.seed) : 0;
-      const stride = Math.max(
-        1,
-        Math.ceil(flightState._billboards.size / maxCount),
-      );
+      const stride = Math.max(1, Math.ceil(icons.count / maxCount));
      const start = seed % stride;
+      const occluder = parts.icons._occluder();
+      const tau = parts.icons._displayTau();

      const result = [];
-      let idx = 0;
-      for (const [icao24, bb] of flightState._billboards) {
-        const shouldTake = (idx - start) % stride === 0;
-        idx++;
-        if (!shouldTake) continue;
+      for (let row = start; row < icons.count; row += stride) {
+        const icao24 = icons.idAt(row);
        if (
          flightState._cockpitContactMode &&
          icao24.toLowerCase() === flightState._cockpitSubjectId
        )
          continue;
        const isTracked = icao24 === flightState._trackedIcao;
-        // Keep planes rendered as a 3D model (billboard hidden) so the detection box
-        // doesn't vanish on the 2D→3D handoff; bb.position stays current while hidden.
+        // Keep planes rendered as a 3D model (icon hidden) so the detection box
+        // doesn't vanish on the 2D→3D handoff.
        const model = flightState._models.get(icao24) ?? null;
        const modelOwnsVisual = parts.rendering._modelOwnsVisual(icao24, model);
-        if (!isTracked && !billboardState(bb).show && !modelOwnsVisual)
-          continue;
+        if (!isTracked && !icons.shown(row) && !modelOwnsVisual) continue;
        const info = flightState.records.data.get(icao24);
        let object = flightState._detectionObjects.get(icao24);
        if (!object) {
@@ -467,21 +450,24 @@ export function createQueries({
            sourceId: icao24,
            type: 'AIR',
            _weldPos: new Cesium.Cartesian3(),
+            _iconPos: new Cesium.Cartesian3(),
          };
          flightState._detectionObjects.set(icao24, object);
        }
+
        // WELD: anchor to whatever actually owns the visual. A model-owned contact is
        // read straight off the translation the fleet tick already wrote into its
        // modelMatrix, so bracket and label sit on the aircraft you can see instead of
-        // on the buried billboard position, which for a grounded plane is ~100 m below
+        // on the buried icon position, which for a grounded plane is ~100 m below
        // and rises only as the coarse ground-floor cell warms. Zero extra sampling and
-        // no `_modelDisplayPosition` call from postRender. Sprite-owned contacts keep
-        // `bb.position` — sprite and bracket are co-located there, so association holds.
+        // no `_modelDisplayPosition` call from postRender. Icon-owned contacts keep
+        // the drawn icon position — icon and bracket are co-located there.
        const spec = modelOwnsVisual
          ? parts.rendering._modelSpec(info?.klass)
          : null;
        const pos = isTracked
-          ? parts.motion._trackedVisualCached() || billboardState(bb).position
+          ? parts.motion._trackedVisualCached() ||
+            icons.position(row, tau, object._iconPos)
          : modelOwnsVisual
            ? modelVisualAnchor(
                modelState(model).modelMatrix,
@@ -491,8 +477,15 @@ export function createQueries({
                  : spec.scale,
                object._weldPos || (object._weldPos = new Cesium.Cartesian3()),
              )
-            : billboardState(bb).position;
-        if (!pos) continue;
+            : icons.position(row, tau, object._iconPos);
+        // An icon past the horizon is not drawn, so it is not detectable.
+        if (
+          !pos ||
+          (!isTracked &&
+            !modelOwnsVisual &&
+            !parts.icons._aboveHorizon(row, pos, occluder))
+        )
+          continue;
        object.position = pos;
        object.skipLabel = isTracked;
        // Card text only — declutter/cohort identity is `object.sourceId` (icao24).
@@ -517,13 +510,9 @@ export function createQueries({
        result.push(object);
        if (result.length >= maxCount) break;
      }
-      if (
-        flightState._detectionObjects.size >
-        flightState._billboards.size + 512
-      ) {
+      if (flightState._detectionObjects.size > icons.count + 512) {
        for (const icao24 of flightState._detectionObjects.keys()) {
-          if (!flightState._billboards.has(icao24))
-            flightState._detectionObjects.delete(icao24);
+          if (!icons.has(icao24)) flightState._detectionObjects.delete(icao24);
        }
      }
      return result;
@@ -583,12 +572,11 @@ export function createQueries({
     * @returns {Array<{id: string, icao24: string, callsign: string|null, position: Cesium.Cartesian3, distance: number, aircraftClass: string|null, altitudeM: number|null, velocityMps: number|null, track: number|null}>}
     */
    getNearby(center, range, maxCount = 50, { includeHidden = false } = {}) {
-      if (
-        !center ||
-        !flightState._billboardCollection ||
-        !flightState._billboardCollection.show
-      )
-        return [];
+      const icons = flightState._icons;
+      if (!center || !icons || !icons.show) return [];
+      const occluder = parts.icons._occluder();
+      const tau = parts.icons._displayTau();
+      const scratch = flightState._scratchNearbyPos;

      const limit = Number.isFinite(maxCount)
        ? Math.max(1, Math.floor(maxCount))
@@ -598,28 +586,30 @@ export function createQueries({

      const nearby = [];

-      for (const [icao24, bb] of flightState._billboards) {
+      for (let row = 0; row < icons.count; row++) {
+        const icao24 = icons.idAt(row);
        const isTracked = icao24 === flightState._trackedIcao;
-        // Keep planes rendered as a 3D model (billboard hidden) so proximity counts
-        // don't drop to zero on the 2D→3D handoff; bb.position stays current while hidden.
+        const trackedPos = isTracked
+          ? parts.motion._trackedDisplayCached()
+          : null; // cached, no recompute (anti-jitter)
+        const drawn = trackedPos || icons.position(row, tau, scratch);
+        // Keep planes rendered as a 3D model (icon hidden) so proximity counts
+        // don't drop to zero on the 2D→3D handoff.
        if (
          !aircraftIncludedInNearby({
            isTracked,
-            billboardShown: billboardState(bb).show,
+            billboardShown:
+              icons.shown(row) &&
+              parts.icons._aboveHorizon(row, drawn, occluder),
            modelRendering: parts.rendering._modelOwnsVisual(icao24),
            includeHidden,
          })
        )
          continue;

-        const trackedPos = isTracked
-          ? parts.motion._trackedDisplayCached()
-          : null; // cached, no recompute (anti-jitter)
-        const pos = trackedPos || billboardState(bb).position;
-        if (!pos) continue;
-
-        const distance = Cesium.Cartesian3.distance(center, pos);
+        const distance = Cesium.Cartesian3.distance(center, drawn);
        if (distance > maxRange) continue;
+        const pos = trackedPos || Cesium.Cartesian3.clone(drawn);

        const info = flightState.records.data.get(icao24);
        const callsign = info?.callsign?.trim() || null;
@@ -651,8 +641,8 @@ export function createQueries({

    /**
     * Return id/label/position for up to maxCount currently rendered aircraft.
-     * Cheap snapshot for voice-tool framing — billboard positions only, no
-     * dead reckoning and no cloning.
+     * Cheap snapshot for voice-tool framing — drawn icon positions, no
+     * extra dead reckoning.
     * @param {number} [maxCount=500] - Maximum number of entries to return.
     * @returns {Array<{id: string, label: string, position: Cesium.Cartesian3, latitude: number, longitude: number, altitudeM: number}>}
     */
@@ -671,34 +661,25 @@ export function createQueries({
     *   holds no data and therefore cannot answer.
     */
    hasContact(icao24) {
-      if (
-        !flightState._billboardCollection ||
-        !flightState._billboardCollection.show ||
-        flightState._billboards.size === 0
-      )
-        return null;
+      const icons = flightState._icons;
+      if (!icons || !icons.show || icons.count === 0) return null;
      if (!icao24) return false;
      const id = String(icao24).trim();
-      return (
-        flightState._billboards.has(id) ||
-        flightState._billboards.has(id.toLowerCase())
-      );
+      return icons.has(id) || icons.has(id.toLowerCase());
    },

    getAllPositions(maxCount = 500) {
-      if (
-        !flightState._billboardCollection ||
-        flightState._billboards.size === 0
-      )
-        return [];
+      const icons = flightState._icons;
+      if (!icons || icons.count === 0) return [];
      const limit = Number.isFinite(maxCount)
        ? Math.max(1, Math.floor(maxCount))
        : 500;
+      const tau = parts.icons._displayTau();

      const result = [];
-      for (const [icao24, bb] of flightState._billboards) {
-        const pos = billboardState(bb).position;
-        if (!pos) continue;
+      for (let row = 0; row < icons.count; row++) {
+        const icao24 = icons.idAt(row);
+        const pos = icons.position(row, tau);
        const carto = Cesium.Cartographic.fromCartesian(
          pos,
          Cesium.Ellipsoid.WGS84,
@@ -741,11 +722,7 @@ export function createQueries({
     * @returns {Array<Object>} See mapAnalystRecord for the record shape.
     */
    getAnalystRecords(maxCount = 2000) {
-      if (
-        !flightState._billboardCollection ||
-        !flightState._billboardCollection.show ||
-        flightState.records.data.size === 0
-      )
+      if (!flightState._icons?.show || flightState.records.data.size === 0)
        return [];
      const limit = Number.isFinite(maxCount)
        ? Math.max(1, Math.floor(maxCount))
@@ -773,8 +750,8 @@ export function createQueries({
    trackById(icao24, { origin = 'programmatic' } = {}) {
      if (!icao24) return false;
      let id = String(icao24).trim();
-      if (!flightState._billboards.has(id)) id = id.toLowerCase();
-      if (!flightState._billboards.has(id)) return false;
+      if (!flightState._icons?.has(id)) id = id.toLowerCase();
+      if (!flightState._icons?.has(id)) return false;
      if (parts.tracking._isExplicitTrackingOrigin(origin))
        parts.tracking._cancelPendingTrackingRestore();
      if (flightState._trackedIcao === id)
@@ -844,7 +821,7 @@ export function createQueries({
      )
        return false;
      let id = String(icao24).trim();
-      if (!flightState._billboards.has(id)) id = id.toLowerCase();
+      if (!flightState._icons?.has(id)) id = id.toLowerCase();
      if (
        id !== flightState._trackedIcao ||
        !flightState._viewer.entities?.contains?.(flightState._trackedEntity) ||
@@ -3,11 +3,9 @@ import assert from 'node:assert/strict';
 import * as Cesium from 'cesium';
 import { createQueries } from './queries.js';
 import { createRendering } from './rendering.js';
-import {
-  billboardState,
-  mirrorBillboard,
-  setBillboard,
-} from '../../data/billboardMirror.js';
+import { createIcons } from './icons.js';
+import { createIconSet } from '../../data/iconSet.js';
+import { writeHoldSegment } from '../../data/iconSegment.js';
 import { mirrorModel, setModel } from '../../data/modelMirror.js';

 function fixture() {
@@ -16,14 +14,11 @@ function fixture() {
    registration: ' N123 ',
    altitude: 1000,
  };
-  const bb = mirrorBillboard({
-    show: true,
-    position: new Cesium.Cartesian3(1, 2, 3),
-  });
+  const icons = createIconSet();
  const flightState = {
    feed: {},
-    _billboardCollection: { show: true },
-    _billboards: new Map([['abc123', bb]]),
+    _icons: icons,
+    _scratchIconRenderTime: new Cesium.JulianDate(),
    _models: new Map(),
    _detectionObjects: new Map(),
    records: { data: new Map([['abc123', info]]) },
@@ -48,8 +43,27 @@ function fixture() {
    motion: { _trackedVisualCached: () => null },
  };
  parts.rendering = createRendering({ flightState, services, parts });
+  parts.icons = createIcons({ flightState, services, parts });
  const queries = createQueries({ flightState, services, parts }).methods;
-  return { flightState, info, bb, parts, queries, formats: () => formats };
+  const row = () => icons.row('abc123');
+  /** Hold the contact's icon at `position`. */
+  const place = (position) => {
+    writeHoldSegment(icons.segments, row(), position, 0);
+    icons.segmentWritten(row());
+  };
+  icons.add('abc123', { id: 'abc123' });
+  place(new Cesium.Cartesian3(1, 2, 3));
+  icons.setShown(row(), true);
+  return {
+    flightState,
+    info,
+    parts,
+    queries,
+    formats: () => formats,
+    place,
+    show: (shown) => icons.setShown(row(), shown),
+    drawn: () => parts.icons._iconPosition('abc123'),
+  };
 }

 test('candidate text follows in-place enrichment without freezing identity or positions', () => {
@@ -57,9 +71,9 @@ test('candidate text follows in-place enrichment without freezing identity or po
  const [first] = f.queries.getDetectableObjects();
  assert.equal(first.id, 'TEST123');
  assert.equal(first.sourceId, 'abc123');
-  setBillboard(f.bb, 'position', new Cesium.Cartesian3(4, 5, 6));
+  f.place(new Cesium.Cartesian3(4, 5, 6));
  assert.equal(f.queries.getDetectableObjects()[0], first);
-  assert.equal(first.position, billboardState(f.bb).position);
+  assert.deepEqual(first.position, f.drawn());
  assert.deepEqual(first.position, new Cesium.Cartesian3(4, 5, 6));
  assert.equal(f.formats(), 1);
  f.info.callsign = ' NEW456 ';
@@ -107,7 +121,7 @@ test('candidate collection resolves models once and keeps handoffs live', (t) =>
    scale: 1,
  });
  f.flightState._models.set('abc123', model);
-  setBillboard(f.bb, 'show', false);
+  f.show(false);
  assert.deepEqual(f.queries.getDetectableObjects(), []);
  model.ready = true;
  assert.equal(f.queries.getDetectableObjects()[0], candidate);
@@ -121,11 +135,8 @@ test('candidate collection resolves models once and keeps handoffs live', (t) =>
  assert.deepEqual(candidate.position, new Cesium.Cartesian3(40, 50, 60));
  setModel(model, 'show', false);
  assert.deepEqual(f.queries.getDetectableObjects(), []);
-  setBillboard(f.bb, 'show', true);
-  assert.equal(
-    f.queries.getDetectableObjects()[0].position,
-    billboardState(f.bb).position,
-  );
+  f.show(true);
+  assert.deepEqual(f.queries.getDetectableObjects()[0].position, f.drawn());
  assert.equal(get.mock.callCount(), 6);
  setModel(model, 'show', true);
  assert.equal(f.parts.rendering._modelOwnsVisual('abc123'), true);
@@ -1,22 +1,14 @@
 import * as Cesium from 'cesium';
-import { cyberSonarBaseAlpha } from '../../cyberSonar.js';
 import { selectModelEligible } from '../../data/modelEligibility.js';
 import { civilAircraftModelSpec } from './modelSpec.js';
 import { CLASS_SCALE_2D } from '../../data/aircraftClass.js';
 import { isEmergency } from '../../data/aircraftEmergency.js';
-import { cockpitContactDotImage } from '../../data/cockpitContactDot.js';
-import { aircraftIcon, TRACKED_ICON_PX } from '../../data/aircraftIcons.js';
-import {
-  cameraPoseSignature,
-  horizonOccluder,
-  screenProjectedRotation,
-} from '../../data/iconOrientation.js';
-import { limitCourseStep, courseSlewCapDps } from '../../data/motionModel.js';
+import { horizonOccluder } from '../../data/iconOrientation.js';
+import { aircraftTreatmentAlpha } from '../../data/aircraftRecession.js';
 import {
  MIL_TINT,
  EMERGENCY_TINT,
  GROUND_SCALE,
-  COCKPIT_CONTACT_SIZE_PX,
  COCKPIT_CIVILIAN_COLOR,
  MODEL_ALT_CEIL_M,
  MODEL_MAX_ALL,
@@ -32,14 +24,9 @@ import {
  TRACKED_MODEL_MIN_PX,
  TRACKED_MODEL_MAX_PX,
  FLEET_DR_INTERVAL_MS,
-  RENDER_DELAY_SEC,
-  COURSE_SLEW_DT_MAX_SEC,
-  ROTATION_REFRESH_MS,
-  COURSE_MAX_DPS,
 } from './policy.js';
 import { AIRCRAFT_ENVIRONMENT_MAP_OPTIONS } from '../../data/aircraftModelLighting.js';
 import { aircraftVisuals } from '../aircraft/visualState.js';
-import { billboardState, setBillboard } from '../../data/billboardMirror.js';
 import { modelState, setModel } from '../../data/modelMirror.js';

 export function createRendering({
@@ -52,14 +39,8 @@ export function createRendering({
  const { isMilitaryIcao } = services.militaryRegistry;
  const { tr3bIconKind, isTr3b } = services.aircraftPresentation;
  const { trackedModelScaleForPixelCap } = services.camera;
-  const {
-    focusNowMs,
-    getFocusTarget,
-    nearFarScalarValueAtDistance,
-    advanceProjectedSpriteFocus,
-  } = services.focus;
-  const { applyAircraftBillboardTreatment, applyAircraftModelTreatment } =
-    services.recession;
+  const { focusNowMs, getFocusTarget } = services.focus;
+  const { applyAircraftModelTreatment } = services.recession;

  /** True while this contact's latest poll broadcast an emergency code. */

@@ -98,22 +79,6 @@ export function createRendering({
    );
  }

-  /** Depth-test policy for aircraft billboards. Round 5 (owner directive
-   *  2026-07-06: "I just want the planes and their lines to ALWAYS be
-   *  visible... evenly applied"): EVERY contact renders depth-test-free at
-   *  every distance — grounded, low, and airborne alike. The photoreal mesh
-   *  writes depth and residual baro/floor error will always leave some sprite
-   *  geometry at or below it; a uniform rule beats the grounded-only /
-   *  low-AGL-only conditions that kept leaving classes of contacts buried
-   *  (2026-07-03 Van Nuys grounded case; 2026-07-06 Austin QNH-below-field
-   *  case). Far-side planes are still removed by the fleet tick's horizon
-   *  occluder, which never depended on depth. Kept as a function so the
-   *  callers' restyle sites stay diff-stable. */
-
-  function _groundDepthDistance() {
-    return Number.POSITIVE_INFINITY;
-  }
-
  function _modelSpec(klass) {
    const cached = flightState._specCache.get(klass);
    if (cached) return cached;
@@ -141,53 +106,6 @@ export function createRendering({
  const _iconKind = (icao24, klass) =>
    tr3bIconKind(icao24, klass, { hot: flightState._irBoost });

-  /** Apply the current normal/cockpit visual contract to one owned fleet billboard. */
-
-  function _applyFleetBillboardPresentation(icao24, bb) {
-    if (!bb) return;
-    const limbScale = flightState._billboardLimbScale.get(bb) ?? 1;
-    const isCockpitContact =
-      flightState._cockpitContactMode && icao24 !== flightState._trackedIcao;
-    const isCockpitNear =
-      isCockpitContact && flightState._cockpitNearContacts.has(icao24);
-    if (isCockpitContact && !isCockpitNear) {
-      const freshnessAlpha = cyberSonarBaseAlpha(bb);
-      bb.image = cockpitContactDotImage();
-      setBillboard(bb, 'width', COCKPIT_CONTACT_SIZE_PX);
-      setBillboard(bb, 'height', COCKPIT_CONTACT_SIZE_PX);
-      setBillboard(bb, 'scale', limbScale);
-      setBillboard(bb, 'scaleByDistance', _cockpitBillboardScaleByDistance());
-      bb.color = _cockpitContactColor(icao24).withAlpha(freshnessAlpha);
-      setBillboard(bb, 'rotation', 0);
-      return;
-    }
-
-    const meta = flightState.records.data.get(icao24);
-    bb.image = aircraftIcon(
-      _iconKind(icao24, meta?.klass),
-      aircraftVisuals.read(bb)?.iconLarge ? TRACKED_ICON_PX : undefined,
-    );
-    setBillboard(bb, 'width', icao24 === flightState._trackedIcao ? 24 : 20);
-    setBillboard(bb, 'height', icao24 === flightState._trackedIcao ? 24 : 20);
-    setBillboard(
-      bb,
-      'scale',
-      _fleetBillboardScale(icao24, meta?.klass) * limbScale,
-    );
-    setBillboard(bb, 'scaleByDistance', _normalBillboardScaleByDistance());
-    bb.color = _fleetBillboardColor(icao24).withAlpha(cyberSonarBaseAlpha(bb));
-  }
-
-  /**
-   * Per-preRender fleet pass at ~12Hz: dead-reckons every untracked billboard,
-   * horizon-culls billboards beyond the limb (no far-side depth with the globe
-   * hidden), and refreshes screen-projected icon rotations whenever the camera
-   * pose changed (plus a 1s drift catch-up while idle). Driven by
-   * scene.preRender — NOT camera.changed, whose granularity is globally
-   * degraded by other layers mutating camera.percentageChanged.
-   * @returns {void}
-   */
-
  /** Model tint, mirroring the billboard color rules. */

  function _modelColor(icao24) {
@@ -272,12 +190,12 @@ export function createRendering({
  /** Everything scene.sampleHeight must NOT hit when snapping a grounded model: the
   *  vertical pick ray at a plane's own lat/lon otherwise lands on its (or a parked
   *  neighbor's) billboard/model instead of the tile skin. Cesium's ray-pick exclusion
-   *  matches picked-object IDs, and every billboard AND model in this layer carries its
+   *  matches picked-object IDs, and every icon AND model in this layer carries its
   *  icao as `id`, so the icao strings cover both; the tracked entity is excluded as the
   *  object itself. Built lazily — only when a sample actually fires (one-shot). */

  function _groundSampleExclusions() {
-    const out = [...flightState._billboards.keys()];
+    const out = parts.icons._iconIds();
    if (flightState._trackedEntity) out.push(flightState._trackedEntity);
    return out;
  }
@@ -323,15 +241,23 @@ export function createRendering({
    );
  }

-  /** Atomically hand one fleet contact from its billboard to a safely placed,
+  /** Atomically hand one fleet contact from its icon to a safely placed,
   * ready 3D model. Missing/loading models and unresolved terrain always leave
-   * the billboard owning the visual, so no render frame can hide both.
+   * the icon owning the visual, so no render frame can hide both.
   * `beforeShow` runs only on the committing path — the per-tick model treatment
   * belongs to a model that is about to draw, not to one still waiting. */

-  function _driveFleetModelHandoff(icao24, model, bb, pos, course, beforeShow) {
+  function _driveFleetModelHandoff(
+    icao24,
+    model,
+    row,
+    pos,
+    course,
+    beforeShow,
+  ) {
+    const icons = flightState._icons;
    if (!model) {
-      setBillboard(bb, 'show', true);
+      icons.setShown(row, true);
      return false;
    }
    const displayPos = _modelDisplayPosition(
@@ -341,7 +267,7 @@ export function createRendering({
    );
    if (!displayPos) {
      setModel(model, 'show', false); // no ground evidence → nothing safe to place a depth-tested model at
-      setBillboard(bb, 'show', true);
+      icons.setShown(row, true);
      return false;
    }
    // The matrix is written BEFORE the readiness test on purpose: a model can flip
@@ -350,12 +276,12 @@ export function createRendering({
    setModel(model, 'modelMatrix', _modelMatrix(displayPos, course));
    if (!model.ready) {
      setModel(model, 'show', false); // not loaded yet → keep the 2D icon, no half-model flash
-      setBillboard(bb, 'show', true);
+      icons.setShown(row, true);
      return false;
    }
    beforeShow?.();
    if (!modelState(model).show) setModel(model, 'show', true);
-    if (billboardState(bb).show) setBillboard(bb, 'show', false); // hand off ONLY once the model renders
+    icons.setShown(row, false); // hand off ONLY once the model renders
    return true;
  }

@@ -443,9 +369,6 @@ export function createRendering({
      (current && aircraftVisuals.read(current)?.specKey !== key) ||
      (!current && flightState._modelPending.has(icao24))
    ) {
-      const bb = flightState._billboards.get(icao24);
-      if (bb && icao24 !== flightState._trackedIcao)
-        setBillboard(bb, 'show', true);
      _releaseModel(icao24);
    }
    if (
@@ -479,9 +402,6 @@ export function createRendering({
        aircraftVisuals.read(model)?.irBoost === flightState._irBoost
      )
        continue; // already right state
-      const bb = flightState._billboards.get(icao);
-      if (bb && icao !== flightState._trackedIcao)
-        setBillboard(bb, 'show', true);
      _releaseModel(icao);
    }
    if (flightState._irReloadQueue.length === 0)
@@ -624,6 +544,7 @@ export function createRendering({
        }
      }
      flightState._models.delete(icao24);
+      _showReleasedIcon(icao24);
    }
    // Do NOT clear _modelPending here — the in-flight load's OWN post-await removes it. Keeping
    // it (a) prevents a duplicate load from starting and (b) keeps the bumped gen entry alive so
@@ -664,9 +585,20 @@ export function createRendering({
        }
      }
    }
+    for (const icao24 of flightState._models.keys()) _showReleasedIcon(icao24);
    flightState._models.clear();
  }

+  /** A released fleet model hands the visual straight back to its icon (the
+   *  tracked contact's entity keeps its own). */
+
+  function _showReleasedIcon(icao24) {
+    const icons = flightState._icons;
+    const row = icons?.row(icao24) ?? -1;
+    if (row >= 0 && icao24 !== flightState._trackedIcao)
+      icons.setShown(row, true);
+  }
+
  /** Destroy the standalone tracked-aircraft model and invalidate any in-flight load. */

  function _releaseTrackedModel() {
@@ -709,8 +641,7 @@ export function createRendering({
    // readout consumers then reuse that exact cached position.
    const pos =
      parts.motion._trackedDisplayPosition(flightState._trackedIcao) ||
-      billboardState(flightState._billboards.get(flightState._trackedIcao))
-        ?.position;
+      parts.icons._iconPosition(flightState._trackedIcao);
    if (!pos) {
      if (flightState._trackedModel)
        setModel(flightState._trackedModel, 'show', false);
@@ -789,9 +720,7 @@ export function createRendering({
          // default here produces a one-frame jump to the Earth's center.
          const currentPos =
            parts.motion._trackedDisplayCached() ||
-            billboardState(
-              flightState._billboards.get(flightState._trackedIcao),
-            )?.position;
+            parts.icons._iconPosition(flightState._trackedIcao);
          if (currentPos) {
            const displayPos = _modelDisplayPosition(
              flightState._trackedIcao,
@@ -859,54 +788,40 @@ export function createRendering({
    }
  }

+  /**
+   * ~12 Hz fleet pass. Motion, rotation, the horizon cull, limb recession and
+   * the two-tier glyph swap all run on the GPU from each row's segment, so this
+   * only re-plans rows whose regime ended, pins grounded contacts to the floor
+   * under them, advances focus de-emphasis while a target exists, and drives
+   * the 3D-model handoff inside the model regime. Driven by scene.preRender.
+   * @returns {void}
+   */
+
  function _fleetTick() {
-    if (
-      !flightState._viewer ||
-      !flightState._billboardCollection ||
-      !flightState._billboardCollection.show
-    )
-      return;
+    const icons = flightState._icons;
+    if (!flightState._viewer || !icons || !icons.show) return;
    const scene = flightState._viewer.scene;
    const camera = flightState._viewer.camera;
    const nowMs = focusNowMs(Date.now());

-    // (The tracked trail head is now the per-frame _trailHeadEntity segment — no 1 Hz
-    // primitive rebuild needed here anymore.)
-
    if (nowMs - flightState._lastFleetTickMs < FLEET_DR_INTERVAL_MS) return;
-    const tickDtSec = flightState._lastFleetTickMs
-      ? Math.min(
-          COURSE_SLEW_DT_MAX_SEC,
-          (nowMs - flightState._lastFleetTickMs) / 1000,
-        )
-      : 0.08;
    flightState._lastFleetTickMs = nowMs;
    // Every contact in this pass shares the same delayed display instant.
-    const renderTime = Cesium.JulianDate.addSeconds(
-      Cesium.JulianDate.now(flightState._scratchFleetRenderTime),
-      -RENDER_DELAY_SEC,
+    const renderTime = parts.icons._displayTime(
      flightState._scratchFleetRenderTime,
    );
+    const tau = icons.seconds(renderTime);

    _drainIrReloadQueue(); // bounded per-tick slice of any pending boost-flip reload
    if (flightState._cockpitContactMode)
      parts.tracking._refreshCockpitNearContacts();
-    const poseSig = cameraPoseSignature(camera);
-    // Only the nearby Cockpit silhouettes need projected course; far dots are
-    // rotation-free. The per-contact gate below keeps the pip path cheap.
-    const doRotations =
-      poseSig !== flightState._lastCamPoseSig ||
-      nowMs - flightState._lastRotPassMs >= ROTATION_REFRESH_MS;
-    if (doRotations) {
-      flightState._lastCamPoseSig = poseSig;
-      flightState._lastRotPassMs = nowMs;
-    }
-
-    const occluder = horizonOccluder(camera);
+    parts.icons._replanExpired(tau);
+    parts.icons._floorGroundedIcons(renderTime, tau, nowMs, camera.positionWC);
    const focusTarget = getFocusTarget();
+    parts.icons._focusIcons(tau, scene, camera, nowMs, focusTarget);

    // 3D model regime: only when enabled AND the camera is zoomed in past the altitude ceiling.
-    // Drop all models the moment we leave it (toggled off / zoomed out) so billboards resume.
+    // Drop all models the moment we leave it (toggled off / zoomed out) so icons resume.
    const useModels = _modelRegimeActive();
    // Drop live models AND invalidate in-flight loads on leaving the regime (else a load that
    // resolves after zoom-out could briefly add a model outside the 3D-model regime).
@@ -915,6 +830,7 @@ export function createRendering({
      (flightState._models.size || flightState._modelPending.size)
    )
      _releaseModels();
+    if (!useModels) return;

    // 3D-model eligibility: by DISTANCE (the mode's add/keep band), with ON-SCREEN PRIORITY under the
    // cap. FOUR passes, visible-first, so the slots are spent on what you can see: (1) KEEP on-screen
@@ -925,273 +841,124 @@ export function createRendering({
    // on-screen plane that wants one (passes 1–2) — a single KEEP-everything pass could fill the cap
    // with off-screen retained models. Pure-distance let off-screen planes eat the cap; pure-frustum
    // filtering dropped near off-screen planes entirely. This does both right.
-    let modelEligible = null;
-    if (useModels) {
-      const cap = _modelCap();
-      const camPos = camera.positionWC;
-      const addM = _modelAddDistM();
-      const addDistSq = addM * addM;
-      const keepM = _modelKeepDistM();
-      const keepDistSq = keepM * keepM;
-      const cull = camera.frustum.computeCullingVolume(
-        camPos,
-        camera.directionWC,
-        camera.upWC,
+    const cap = _modelCap();
+    const camPos = camera.positionWC;
+    const addM = _modelAddDistM();
+    const addDistSq = addM * addM;
+    const keepM = _modelKeepDistM();
+    const keepDistSq = keepM * keepM;
+    const cull = camera.frustum.computeCullingVolume(
+      camPos,
+      camera.directionWC,
+      camera.upWC,
+    );
+    // Candidates = planes within the KEEP radius, nearest first, each tagged with on-screen-ness.
+    const cand = [];
+    for (let row = 0; row < icons.count; row++) {
+      const icao = icons.idAt(row);
+      if (icao === flightState._trackedIcao) continue;
+      // A converted TR-3B renders as an icon and can never take a model, so
+      // it must not occupy a CAP SLOT either — excluded here at selection time,
+      // not just at the handoff below, or accumulated conversions would starve
+      // ordinary contacts of 3D models. (The handoff guard stays as defence.)
+      if (isTr3b(icao)) continue;
+      // Ground planes compete for model slots like everyone else (owner decision
+      // 2026-07-03: "3D mode is respected regardless of whether a plane is on the
+      // ground or in the air — no distinction"). The cap + nearest-first ordering
+      // below already bound airport clusters; grounded placement is handled by the
+      // one-shot ground snap in _modelDisplayPosition.
+      const position = icons.position(
+        row,
+        tau,
+        flightState._scratchModelBS.center,
      );
-      // Candidates = planes within the KEEP radius, nearest first, each tagged with on-screen-ness.
-      const cand = [];
-      for (const [icao, bb] of flightState._billboards) {
-        if (icao === flightState._trackedIcao) continue;
-        // A converted TR-3B renders as a billboard and can never take a model, so
-        // it must not occupy a CAP SLOT either — excluded here at selection time,
-        // not just at the handoff below, or accumulated conversions would starve
-        // ordinary contacts of 3D models. (The handoff guard stays as defence.)
-        if (isTr3b(icao)) continue;
-        // Ground planes compete for model slots like everyone else (owner decision
-        // 2026-07-03: "3D mode is respected regardless of whether a plane is on the
-        // ground or in the air — no distinction"). The cap + nearest-first ordering
-        // below already bound airport clusters; grounded placement is handled by the
-        // one-shot ground snap in _modelDisplayPosition.
-        const { position } = billboardState(bb);
-        const d2 = Cesium.Cartesian3.distanceSquared(camPos, position);
-        if (d2 > keepDistSq) continue; // beyond the keep radius → never eligible
-        Cesium.Cartesian3.clone(position, flightState._scratchModelBS.center);
-        cand.push([
-          icao,
-          d2,
-          cull.computeVisibility(flightState._scratchModelBS) !==
-            Cesium.Intersect.OUTSIDE,
-        ]);
-      }
-      cand.sort((a, b) => a[1] - b[1]); // nearest first
-      if (cand.length > cap && nowMs - flightState._lastModelCapWarnMs > 5000) {
-        console.warn(
-          `[Data:Flights] ${cand.length} planes in 3D range; capped at ${cap} (${flightState._models3dMode}). On-screen planes are prioritized.`,
-        );
-        flightState._lastModelCapWarnMs = nowMs;
-      }
-      modelEligible = selectModelEligible(cand, {
-        cap,
-        addDistSq,
-        isModeled: (icao) => flightState._models.has(icao),
-      });
-      const toRelease = [];
-      for (const icao of flightState._models.keys()) {
-        if (icao !== flightState._trackedIcao && !modelEligible.has(icao))
-          toRelease.push(icao);
-      }
-      for (const icao of toRelease) _releaseModel(icao);
+      const d2 = Cesium.Cartesian3.distanceSquared(camPos, position);
+      if (d2 > keepDistSq) continue; // beyond the keep radius → never eligible
+      cand.push([
+        icao,
+        d2,
+        cull.computeVisibility(flightState._scratchModelBS) !==
+          Cesium.Intersect.OUTSIDE,
+      ]);
    }
-
-    for (const [icao24, bb] of flightState._billboards) {
-      if (icao24 === flightState._trackedIcao) continue; // tracked entity owns its own motion
-      const icon = billboardState(bb);
-
-      const info = flightState.records.data.get(icao24);
-
-      const dr = parts.motion._deadReckon(
-        icao24,
-        flightState._scratchFleetPos,
-        renderTime,
+    cand.sort((a, b) => a[1] - b[1]); // nearest first
+    if (cand.length > cap && nowMs - flightState._lastModelCapWarnMs > 5000) {
+      console.warn(
+        `[Data:Flights] ${cand.length} planes in 3D range; capped at ${cap} (${flightState._models3dMode}). On-screen planes are prioritized.`,
      );
-      // The dead-reckoned point drifts away from the fix whose cell supplied the
-      // height, so a grounded contact's sprite ends up under the mesh it taxied
-      // (or coasted) over. Re-floor at the DISPLAYED coordinate — read-only, and
-      // never while a 3D model owns the visual (T7).
-      const display = parts.motion._floorGroundedDisplayPosition(
-        icao24,
-        info,
-        dr,
-        _modelOwnsVisual(icao24),
-        nowMs,
-      );
-      // Gate the write — assigning Billboard.position dirties the whole
-      // collection's vertex buffer, so skip sub-meter moves.
-      if (
-        display &&
-        Cesium.Cartesian3.distanceSquared(display, icon.position) > 1.0
-      ) {
-        setBillboard(bb, 'position', display);
-      }
+      flightState._lastModelCapWarnMs = nowMs;
+    }
+    const modelEligible = selectModelEligible(cand, {
+      cap,
+      addDistSq,
+      isModeled: (icao) => flightState._models.has(icao),
+    });
+    const toRelease = [];
+    for (const icao of flightState._models.keys()) {
+      if (icao !== flightState._trackedIcao && !modelEligible.has(icao))
+        toRelease.push(icao);
+    }
+    for (const icao of toRelease) _releaseModel(icao);

-      // Round 6: occlusion-test a LIFTED point for contacts rendering below
-      // (or within a wingspan of) the ellipsoid — EllipsoidalOccluder judges a
-      // sub-ellipsoid point near the limb "beyond the horizon" and the fleet
-      // pass would hide a plane that is really just low over high-N terrain
-      // waiting for its floor to warm (ATL grounded contacts at geoid −31 m).
-      const beyondHorizon = !occluder.isPointVisible(
-        flightState._cullPositions.get(icao24) || icon.position,
-      );
-      // A billboard flipping INTO view (horizon reveal while the camera idles)
-      // gets its rotation refreshed THIS tick even without a pose change —
-      // otherwise it reappears wearing its stale (often creation-north) nose for
-      // up to ROTATION_REFRESH_MS. (Model-handed-off planes also read show=false
-      // here; harmless — the model branch below `continue`s past the rotation.)
-      const revealed = !beyondHorizon && !icon.show;
-      if (icon.show === beyondHorizon) setBillboard(bb, 'show', !beyondHorizon);
-      if (beyondHorizon) {
-        // Also hide any 3D model — otherwise a model that crossed the limb would keep
-        // rendering through the hidden globe at its last matrix.
+    // 3D model takes over from the icon for eligible planes. GAP-PROOF: the icon stays shown
+    // until the model is actually READY to render, so a plane is never both iconless AND
+    // modelless (the "planes vanish when 3D turns on" bug). Position the model every tick
+    // regardless so it's framed the instant it becomes ready. Converted TR-3Bs stay 2D on
+    // purpose: the Easter egg IS the triangle, and there is no GLB for it.
+    const occluder = horizonOccluder(camera);
+    for (const icao24 of modelEligible) {
+      if (isTr3b(icao24)) continue;
+      const row = icons.row(icao24);
+      if (row < 0) continue;
+      const position = icons.position(row, tau, flightState._scratchFleetPos);
+      if (!parts.icons._aboveHorizon(row, position, occluder)) {
+        // A model that crossed the limb would keep rendering through the
+        // hidden globe at its last matrix; the icon's own cull is on the GPU.
        const m = flightState._models.get(icao24);
        if (m && modelState(m)?.show) setModel(m, 'show', false);
        continue;
      }
-
-      // One order-independent write site composes freshness × focus × limb haze
-      // for alpha, and base class/ground scale × limb taper for scale. Cesium's
-      // locked NearFarScalar remains a separate multiplicative stage. This
-      // narrowly amends always-visible rendering without count culling or zero
-      // alpha; nearer focus behavior remains tunable rather than universal.
-      const cameraDistanceM = Cesium.Cartesian3.distance(
-        camera.positionWC,
-        icon.position,
+      _ensureModel(icao24);
+      const model = flightState._models.get(icao24);
+      const cameraDistanceM = Cesium.Cartesian3.distance(camPos, position);
+      _driveFleetModelHandoff(
+        icao24,
+        model,
+        row,
+        position,
+        icons.course(row, tau),
+        () => {
+          applyAircraftModelTreatment({
+            model,
+            // IR boost must survive the per-tick treatment write — otherwise
+            // any alpha change would repaint the ordinary tint over the hot
+            // white. Boosted models also skip the recession fade: hot targets
+            // stay full-strength at any range (icons keep their normal
+            // fade — full-opacity glyph walls read as overwhelming).
+            baseColor: flightState._irBoost
+              ? Cesium.Color.WHITE
+              : _modelColor(icao24),
+            alpha: flightState._irBoost
+              ? 1
+              : aircraftTreatmentAlpha({
+                  baseAlpha: icons.alpha(row),
+                  focusFactor: icons.focus(row),
+                  cameraDistanceM,
+                  cameraHeightM: camera.positionCartographic?.height,
+                }),
+          });
+        },
      );
-      const distanceScale = nearFarScalarValueAtDistance(
-        icon.scaleByDistance,
-        cameraDistanceM,
-      );
-      const focus = advanceProjectedSpriteFocus(
-        bb,
-        icon.position,
-        scene,
-        camera,
-        nowMs,
-        focusTarget,
-        undefined,
-        (icon.width || 20) * (icon.scale || 1) * distanceScale * 0.5,
-        (icon.height || 20) * (icon.scale || 1) * distanceScale * 0.5,
-      );
-      const isCockpitNear =
-        flightState._cockpitContactMode &&
-        flightState._cockpitNearContacts.has(icao24);
-      const layerBaseColor =
-        flightState._cockpitContactMode && !isCockpitNear
-          ? _cockpitContactColor(icao24, info)
-          : _fleetBillboardColor(icao24, info);
-      const baseColor = layerBaseColor;
-      const treatment = applyAircraftBillboardTreatment({
-        billboard: bb,
-        baseScale:
-          flightState._cockpitContactMode && !isCockpitNear
-            ? 1
-            : _fleetBillboardScale(icao24, info?.klass),
-        baseAlpha: flightState.records.missingPolls.get(icao24) ? 0.45 : 1,
-        baseColor,
-        focusFactor: focus.factor,
-        cameraDistanceM,
-        cameraHeightM: camera.positionCartographic?.height,
-      });
-      flightState._billboardLimbScale.set(bb, treatment.factors.scale);
-      // Two-tier glyph raster (owner playtest 2026-08-16): the billboard atlas
-      // has no mipmaps, so no single texture stays crisp across the ~25–150
-      // device-px range scaleByDistance produces. Swap between the 64 px fleet
-      // raster and the 192 px close raster on the billboard's ACTUAL on-screen
-      // size — post-treatment bb.scale, so focus/limb recession counts — with
-      // hysteresis so zoom oscillation never thrashes the atlas.
-      if (!flightState._cockpitContactMode || isCockpitNear) {
-        const glyphDevPx =
-          (icon.width || 20) *
-          (icon.scale || 1) *
-          distanceScale *
-          (globalThis.devicePixelRatio || 1);
-        const visual = aircraftVisuals.write(bb);
-        const wantLarge = visual.iconLarge ? glyphDevPx > 56 : glyphDevPx > 76;
-        if (wantLarge !== !!visual.iconLarge) {
-          visual.iconLarge = wantLarge;
-          bb.image = aircraftIcon(
-            _iconKind(icao24, info?.klass),
-            wantLarge ? TRACKED_ICON_PX : undefined,
-          );
-        }
-      }
-
-      // Smoothed display course: the path direction _deadReckon just reported
-      // for THIS aircraft (nothing else calls _deadReckon in between), rate-
-      // limited so segment-boundary course steps glide instead of snapping.
-      // The slew cap eases toward COURSE_MIN_DPS at low speed, and a hovering
-      // aircraft (hold flag) keeps its previous nose direction outright.
-      const rawCourse =
-        flightState._drCourseDeg != null
-          ? flightState._drCourseDeg
-          : (info && info.true_track) || 0;
-      const prevCourse = flightState._displayCourse.get(icao24);
-      const course =
-        flightState._drCourseHold && prevCourse != null
-          ? prevCourse
-          : limitCourseStep(
-              prevCourse,
-              rawCourse,
-              courseSlewCapDps(
-                flightState._drSpeedMps != null
-                  ? flightState._drSpeedMps
-                  : ((info && info.velocity) ?? NaN),
-                COURSE_MAX_DPS,
-              ),
-              tickDtSec,
-            );
-      flightState._displayCourse.set(icao24, course);
-
-      // 3D model takes over from the billboard for in-view planes (modelEligible). GAP-PROOF: the
-      // billboard stays shown until the model is actually READY to render, so a plane is never both
-      // iconless AND modelless (the "planes vanish when 3D turns on" bug). Position the model every
-      // tick regardless so it's framed the instant it becomes ready.
-      // Converted TR-3Bs stay 2D on purpose: the Easter egg IS the triangle, and
-      // there is no GLB for it, so the model handoff is suppressed rather than
-      // fed a stand-in mesh. The billboard keeps rendering (and keeps satisfying
-      // the getNearby/getDetectableObjects `bb.show` visibility guards), so a
-      // converted contact still works in Contacts and Cockpit.
-      if (useModels && dr && modelEligible.has(icao24) && !isTr3b(icao24)) {
-        _ensureModel(icao24);
-        const model = flightState._models.get(icao24);
-        const ownsVisual = _driveFleetModelHandoff(
-          icao24,
-          model,
-          bb,
-          dr,
-          course,
-          () => {
-            applyAircraftModelTreatment({
-              model,
-              // IR boost must survive the per-tick treatment write — otherwise
-              // any alpha change would repaint the ordinary tint over the hot
-              // white. Boosted models also skip the recession fade: hot targets
-              // stay full-strength at any range (billboards keep their normal
-              // fade — full-opacity glyph walls read as overwhelming).
-              baseColor: flightState._irBoost
-                ? Cesium.Color.WHITE
-                : _modelColor(icao24),
-              alpha: flightState._irBoost ? 1 : treatment.alpha,
-            });
-          },
-        );
-        if (ownsVisual) continue; // skip billboard rotation
-      }
-
-      if (
-        (!flightState._cockpitContactMode || isCockpitNear) &&
-        (doRotations || revealed)
-      ) {
-        const rot = screenProjectedRotation(
-          scene,
-          icon.position,
-          course,
-          icon.rotation,
-        );
-        if (rot !== null && Math.abs(rot - icon.rotation) > 0.002) {
-          setBillboard(bb, 'rotation', rot);
-        }
-      }
    }
  }
  return {
    _fleetBillboardColor,
    _fleetBillboardScale,
-    _groundDepthDistance,
+    _cockpitContactColor,
    _modelSpec,
    _normalBillboardScaleByDistance,
    _cockpitBillboardScaleByDistance,
    _iconKind,
-    _applyFleetBillboardPresentation,
    _modelColor,
    _modelRegimeActive,
    _modelCap,
@@ -1,13 +1,10 @@
 import * as Cesium from 'cesium';
-import { cyberSonarBaseAlpha } from '../../cyberSonar.js';
 import {
  turnRateFromFixHistory,
  liftRepeatedGroundFix,
  synthesizeForwardKinematicsFix,
 } from '../../data/motionModel.js';
-import { aircraftIcon } from '../../data/aircraftIcons.js';
 import { POSITION_HISTORY_LIMIT } from './recordPolicy.js';
-import { addBillboard } from '../../data/billboardMirror.js';

 /** Apply reconciled aircraft records to Cesium resources and follow state. */
 export function createFlightSnapshotRenderer({
@@ -19,6 +16,7 @@ export function createFlightSnapshotRenderer({
  rendering,
  tracking,
  motion,
+  icons,
  enrichment,
  queries,
 }) {
@@ -53,17 +51,8 @@ export function createFlightSnapshotRenderer({
      // which hands off on untrack).
      const isMil = isMilitaryIcao(icao24);
      if (isMil && tracking._militaryLayerSuppresses(icao24)) {
-        const dupe = flightState._billboards.get(icao24);
-        if (dupe) {
-          flightState._billboardCollection.remove(dupe);
-          flightState._billboards.delete(icao24);
-          rendering._releaseModel(icao24); // military-suppression: drop any 3D model too
-          records.forget(icao24);
-          flightState._cullPositions.delete(icao24);
-          flightState._positionHistory.delete(icao24);
-          flightState._displayCourse.delete(icao24);
-          flightState._groundSnap.forget(icao24);
-        }
+        // Military-suppression: drop the duplicate with any 3D model too.
+        if (flightState._icons.has(icao24)) icons._forgetContact(icao24);
        continue;
      }

@@ -84,12 +73,12 @@ export function createFlightSnapshotRenderer({
      );
      // Either flip retires the previous one-shot ground sample.
      if (groundFlipped) flightState._groundSnap.forget(icao24);
-      flightState._cullPositions.set(
-        icao24,
-        meta.renderAltitudeM < 10
-          ? Cesium.Cartesian3.fromDegrees(meta.rawLon, meta.rawLat, 12)
-          : null,
-      );
+      if (meta.onGround) {
+        flightState._grounded.add(icao24);
+      } else if (flightState._grounded.delete(icao24)) {
+        flightState._floorPinned.delete(icao24);
+        motion._retireDisplayFloorState(icao24, Date.now());
+      }
      const isTracked = icao24 === flightState._trackedIcao;

      // Append to position history stamped with the FEED's fix epoch
@@ -153,72 +142,18 @@ export function createFlightSnapshotRenderer({
        }
      }

-      if (flightState._billboards.has(icao24)) {
-        const bb = flightState._billboards.get(icao24);
-        // Reclassify if the category resolved/changed (first extended poll);
-        // a ground flip (landing/takeoff) re-scales the SAME billboard in
-        // place — the transition is a restyle, never a removal.
-        // Round 5: depth policy is uniform (always depth-test-free, see
-        // _groundDepthDistance) — nothing to flip on landing/takeoff.
-        // Position AND rotation are owned by the fleet pass (_fleetTick);
-        // course changes land on the next rotation pass (forced below).
-        if (!isTracked) {
-          // Refresh affiliation hue without clobbering the tick-owned
-          // freshness × focus × horizon alpha composition.
-          bb.color = rendering
-            ._fleetBillboardColor(icao24)
-            .withAlpha(cyberSonarBaseAlpha(bb));
-        }
-        if (
-          prevMeta?.klass !== meta.klass ||
-          groundFlipped ||
-          flightState._cockpitContactMode
-        ) {
-          rendering._applyFleetBillboardPresentation(icao24, bb);
-        }
+      if (flightState._icons.has(icao24)) {
+        // Reclassification, a ground flip (a restyle, never a removal), a
+        // freshness change and the cockpit contract all land on the row's
+        // style; motion re-plans from the updated history.
+        icons._applyIconPresentation(icao24);
+        icons._planIcon(icao24);
        // Poll-path class change (category updates): same model resync rule
        // as the enrichment path — the class's GLB/scale may have changed.
        if (prevMeta?.klass !== meta.klass) rendering._syncModelToClass(icao24);
      } else {
-        // Start where the fleet pass will draw it: the fleet renders behind
-        // real time, so a fresh contact's displayed position is its fix
-        // projected back to that delayed time, and a grounded contact is then
-        // lifted onto the floor under that delayed position. Creating it at
-        // the raw fix drew it ahead until the next fleet tick snapped it back;
-        // skipping the floor started a taxiing contact low and then raised it.
-        const delayed = motion._deadReckon(icao24, new Cesium.Cartesian3());
-        const displayed =
-          (delayed &&
-            motion._floorGroundedDisplayPosition(
-              icao24,
-              flightState.records.data.get(icao24) || meta,
-              delayed,
-              rendering._modelOwnsVisual(icao24),
-            )) ||
-          position;
-        const bb = addBillboard(flightState._billboardCollection, {
-          position: displayed,
-          image: aircraftIcon(rendering._iconKind(icao24, meta.klass)),
-          width: isTracked ? 24 : 20,
-          height: isTracked ? 24 : 20,
-          scale: rendering._fleetBillboardScale(icao24, meta.klass),
-          // Screen-projected rotation lands on the next fleet tick.
-          rotation: 0,
-          alignedAxis: Cesium.Cartesian3.ZERO,
-          color: isTracked
-            ? Cesium.Color.CYAN
-            : rendering._fleetBillboardColor(icao24),
-          sizeInMeters: false,
-          scaleByDistance: rendering._normalBillboardScaleByDistance(),
-          // Grounded/near-surface planes sit at/below the photoreal tile
-          // surface — render them depth-test-free so they never vanish up
-          // close (_groundDepthDistance).
-          disableDepthTestDistance: rendering._groundDepthDistance(),
-          id: icao24,
-          show: !isTracked, // hidden if currently tracked (entity replaces it)
-        });
-        flightState._billboards.set(icao24, bb);
-        rendering._applyFleetBillboardPresentation(icao24, bb);
+        // Hidden while tracked: the tracked entity replaces it.
+        icons._addIcon(icao24);
      }

      // Takeoff while TRACKED: ground traffic drew no trail, so start one
@@ -240,8 +175,12 @@ export function createFlightSnapshotRenderer({
    // EXCEPTION: likely-landed planes (last fix low + slow) get only
    // LANDED_MISSING_POLL_LIMIT — their disappearance means "landed", not a
    // feed gap, and the full grace left phantom planes parked at airports.
-    for (const [icao24, bb] of flightState._billboards) {
-      if (currentIcaos.has(icao24)) continue;
+    const absentIds = [];
+    for (let row = 0; row < flightState._icons.count; row++) {
+      const icao24 = flightState._icons.idAt(row);
+      if (!currentIcaos.has(icao24)) absentIds.push(icao24);
+    }
+    for (const icao24 of absentIds) {
      const absence = records.absence(icao24, {
        complete: snapshot.complete,
        retainIds: snapshot.retainIds,
@@ -249,8 +188,9 @@ export function createFlightSnapshotRenderer({
      });
      if (absence === 'retain') continue;
      if (absence === 'stale') {
+        icons._applyIconPresentation(icao24); // the faded freshness alpha
        if (icao24 === flightState._trackedIcao && flightState._trackedEntity) {
-          // Honest readout: the tracked plane has no faded billboard (its
+          // Honest readout: the tracked plane has no faded icon (its
          // entity owns the visual), so refresh the label — with icao24 now
          // in _missingPolls, _trackedLabelText appends the STALE cue so
          // last-known velocity/altitude aren't presented as live.
@@ -269,20 +209,9 @@ export function createFlightSnapshotRenderer({
        tracking._clearTracking(false, { evicted: true });
      }

-      flightState._billboardCollection.remove(bb);
-      flightState._billboards.delete(icao24);
-      rendering._releaseModel(icao24); // aged-out aircraft: drop its 3D model (no orphan / cap leak)
-      records.forget(icao24);
-      flightState._cullPositions.delete(icao24);
-      flightState._positionHistory.delete(icao24);
-      flightState._displayCourse.delete(icao24);
-      flightState._groundSnap.forget(icao24);
-      flightState._displayFloorState.delete(icao24);
+      icons._forgetContact(icao24); // aged out: its 3D model goes too (no orphan / cap leak)
    }

-    // Fresh courses arrived — force a rotation pass on the next fleet tick
-    flightState._lastCamPoseSig = '';
-
    // Ambient type enrichment: give ON-SCREEN planes real types (bounded
    // sweep — see _sweepAmbientEnrichment; internally fail-silent).
    enrichment._sweepAmbientEnrichment();
@@ -307,7 +236,7 @@ export function createFlightSnapshotRenderer({
    // aircraft instead of the pavement.
    sampleMeshFloorCells(flightState._viewer?.scene, floorWarmPoints, {
      excludeObjects: [
-        ...flightState._billboards.values(),
+        ...icons._iconIds(),
        ...flightState._models.values(),
        flightState._trackedModel,
      ].filter(Boolean),
@@ -327,6 +256,6 @@ export function createFlightSnapshotRenderer({
    // in place is safe (the DR extrapolates a zero-velocity fix).
    motion._refloorStaleGroundedContacts(currentIcaos);

-    return { count: flightState._billboards.size, ids: acceptedSnapshotIcaos };
+    return { count: flightState._icons.count, ids: acceptedSnapshotIcaos };
  };
 }
@@ -11,7 +11,6 @@ export function createFlightState({ source, services }) {
    ...services.geoid,
    ...services.groundFloor,
  });
-  flightState._cullPositions = new Map();

  /** Per-class model spec. Hangar-fleet classes (CLASS_MODEL_REAL) ship GLBs
   *  vertex-baked to real-world METERS in the airplane.glb axis convention, so
@@ -91,22 +90,37 @@ export function createFlightState({ source, services }) {
    1.0,
  );
  // frustum-visibility test
-  /** Last limb taper per billboard, retained across class/ground/cockpit repaints. */
-
-  flightState._billboardLimbScale = new WeakMap();
  // keep last N positions per aircraft

  // ---------------------------------------------------------------------------
  // Module-level state: billboard collection and per-aircraft lookup maps
  // ---------------------------------------------------------------------------

-  /** @type {Cesium.BillboardCollection|null} */
+  /** Every contact's icon row (see icons.js); null outside a layer lifetime. */

-  flightState._billboardCollection = null;
+  flightState._icons = null;

-  /** @type {Map<string, Cesium.Billboard>} icao24 -> billboard primitive */
+  /** The primitive drawing `_icons`. */

-  flightState._billboards = new Map();
+  flightState._iconPrimitive = null;
+
+  flightState._scratchIconRenderTime = new Cesium.JulianDate();
+
+  /** Contacts whose latest poll put them on the ground. */
+
+  flightState._grounded = new Set();
+
+  /** Grounded contacts the floor currently lifts; their rows hold CPU positions. */
+
+  flightState._floorPinned = new Set();
+
+  /** Fleet ticks since start; far grounded rows take their floor turn by it. */
+
+  flightState._floorTick = 0;
+
+  /** Rows still away from full focus emphasis after the last focus pass. */
+
+  flightState._iconFocusActive = 0;

  /** Stable lightweight records reused by the detection overlay between polls. */

@@ -204,14 +218,6 @@ export function createFlightState({ source, services }) {

  flightState._lastFleetTickMs = 0;

-  /** @type {string} Camera pose signature at the last rotation pass */
-
-  flightState._lastCamPoseSig = '';
-
-  /** @type {number} Epoch ms of the last full rotation pass */
-
-  flightState._lastRotPassMs = 0;
-
  /** @type {number} Last computed rotation for the tracked entity (radians) */

  flightState._lastTrackedRotation = 0;
@@ -250,6 +256,10 @@ export function createFlightState({ source, services }) {

  flightState._scratchFleetPos = new Cesium.Cartesian3();

+  flightState._scratchCockpitPos = new Cesium.Cartesian3();
+
+  flightState._scratchNearbyPos = new Cesium.Cartesian3();
+
  flightState._scratchSonarScreen = new Cesium.Cartesian2();

  flightState._scratchDrRaw = new Cesium.Cartesian3();
@@ -1,7 +1,8 @@
 import * as Cesium from 'cesium';
 import { CYAN_TRANSPARENT } from './policy.js';
-import { mirrorBillboard } from '../../data/billboardMirror.js';
 import { mirrorModel } from '../../data/modelMirror.js';
+import { createIconSet } from '../../data/iconSet.js';
+import { writeHoldSegment } from '../../data/iconSegment.js';

 export function createTesting({
  flightState,
@@ -38,6 +39,19 @@ export function createTesting({
    flightState._displayFloorState.clear();
  }

+  /** Give a test contact an icon row held at `billboard.position`, shown as
+   *  `billboard.show` says (hidden by default while tracked). */
+
+  function _seedIconForTest(icao24, billboard, tracked) {
+    const icons = flightState._icons;
+    const row = icons.add(icao24, { layer: 'flights', id: icao24 });
+    if (billboard?.position)
+      writeHoldSegment(icons.segments, row, billboard.position, 0);
+    icons.segmentWritten(row);
+    icons.setShown(row, billboard?.show ?? !tracked);
+    return row;
+  }
+
  /**
   * Seed only the mutable state needed to exercise tracked-card refreshes through
   * the production poll reconciler. Tests still call `flightsLayer.update()`;
@@ -46,13 +60,14 @@ export function createTesting({
   * @param {string} state.icao24
   * @param {object} state.entity
   * @param {object} state.meta
-   * @param {object} state.billboard
-   * @param {object} state.billboardCollection
+   * @param {{position?: Cesium.Cartesian3, show?: boolean}} [state.billboard]
+   *   Where the contact's icon is held, and whether it is shown.
+   * @param {{show?: boolean}} [state.billboardCollection] Layer visibility.
   * @param {object} state.viewer
   * @param {Array<Object>} [state.history=[]]
   * @param {boolean} [state.tracked=true]
   * @param {Iterable<[string, object]>} [state.models=[]] - Fleet 3D models keyed
-   *   by icao24, for the billboard-hidden/model-shown handoff state.
+   *   by icao24, for the icon-hidden/model-shown handoff state.
   */

  function _setTrackedFlightRefreshStateForTest({
@@ -69,9 +84,13 @@ export function createTesting({
  }) {
    flightState._viewer = viewer;
    flightState._modelCollection = modelCollection;
-    flightState._billboardCollection = billboardCollection;
-    flightState._billboards = new Map([[icao24, mirrorBillboard(billboard)]]);
-    flightState._cullPositions.clear();
+    flightState._icons = createIconSet({
+      epoch: parts.icons._displayTime(new Cesium.JulianDate()),
+    });
+    flightState._icons.show = billboardCollection?.show ?? true;
+    flightState._grounded.clear();
+    flightState._floorPinned.clear();
+    _seedIconForTest(icao24, billboard, tracked);
    flightState._models.clear();
    for (const [key, model] of models)
      flightState._models.set(key, mirrorModel(model));
@@ -120,7 +139,7 @@ export function createTesting({
    billboard,
    history = [],
  }) {
-    flightState._billboards.set(icao24, mirrorBillboard(billboard));
+    _seedIconForTest(icao24, billboard, false);
    flightState.records.data.set(icao24, meta);
    flightState._positionHistory.set(icao24, history);
  }
@@ -181,25 +200,64 @@ export function createTesting({
      : Cesium.Color.CYAN;
  }

-  /** Drive the exact fleet billboard-to-model handoff used by `_fleetTick`. */
+  /** Drive the exact fleet icon-to-model handoff used by `_fleetTick`. */

  function _driveFleetModelHandoffForTest({ icao24, position, course = 0 }) {
    return parts.rendering._driveFleetModelHandoff(
      icao24,
      flightState._models.get(icao24),
-      flightState._billboards.get(icao24),
+      flightState._icons.row(icao24),
      position,
      course,
    );
  }

+  /** Where a contact's icon is drawn now and whether the layer shows it. */
+
+  function _iconForTest(icao24) {
+    const position = parts.icons._iconPosition(icao24);
+    return position
+      ? {
+          position,
+          shown: parts.icons._iconShown(icao24),
+          course: parts.icons._iconCourse(icao24),
+        }
+      : null;
+  }
+
  /** Exercise the exact asynchronous fleet loader and return its admitted model. */

  async function _ensureFleetModelForTest(icao24) {
    await parts.rendering._ensureModel(icao24);
    return flightState._models.get(icao24) || null;
  }
+  /** Show or hide a contact's icon as a handoff would, or hold it somewhere. */
+
+  function _setIconForTest(icao24, { shown, position } = {}) {
+    const icons = flightState._icons;
+    const row = icons?.row(icao24) ?? -1;
+    if (row < 0) return;
+    if (shown !== undefined) icons.setShown(row, shown);
+    if (position) {
+      writeHoldSegment(icons.segments, row, position, 0);
+      icons.segmentWritten(row);
+    }
+  }
+
+  /** Run the fleet tick's grounded floor pass once, at `renderTime`. */
+
+  function _floorGroundedIconsForTest(renderTime, cameraPosition) {
+    const icons = flightState._icons;
+    parts.icons._floorGroundedIcons(
+      renderTime,
+      icons.seconds(renderTime),
+      Date.now(),
+      cameraPosition,
+    );
+  }
  return {
+    _floorGroundedIconsForTest,
+    _setIconForTest,
    _floorGroundedDisplayPositionForTest,
    _clearDisplayFloorStateForTest,
    _setTrackedFlightRefreshStateForTest,
@@ -214,6 +272,7 @@ export function createTesting({
    _updateTrackedModelForTest,
    _trackedBillboardColorForTest,
    _driveFleetModelHandoffForTest,
+    _iconForTest,
    _ensureFleetModelForTest,
  };
 }
@@ -27,7 +27,6 @@ import {
 } from './policy.js';
 import { roundHeadingDegrees } from '../../data/headingDegrees.js';
 import { entityRecord, readEntityRecord } from '../../data/entityRecords.js';
-import { billboardState, setBillboard } from '../../data/billboardMirror.js';

 export function createTracking({
  flightState,
@@ -65,9 +64,9 @@ export function createTracking({
  }

  function _publishTrackedSelection(icao24, origin = 'programmatic') {
-    const bb = flightState._billboards.get(icao24);
+    const position = parts.icons._iconPosition(icao24);
    const info = flightState.records.data.get(icao24);
-    if (!billboardState(bb)?.position || !info) return false;
+    if (!position || !info) return false;
    if (flightState._trackedEntity)
      entityRecord(flightState._trackedEntity).selectionOrigin = origin;
    _emitAwarenessEvent('gev:awareness-subject-selected', {
@@ -78,7 +77,7 @@ export function createTracking({
      // a callsign-less contact reached Context as its raw hex even once adsbdb
      // had supplied a registration. Identity below stays `icao24`.
      label: parts.queries._contactLabel(icao24, info),
-      position: Cesium.Cartesian3.clone(billboardState(bb).position),
+      position,
      origin,
    });
    selectTrackedSubjectContext(_contextSubjectMetadata(icao24));
@@ -163,9 +162,12 @@ export function createTracking({
    }
    const previous = flightState._cockpitNearContacts;
    const distancesSquared = [];
-    for (const [icao24, bb] of flightState._billboards) {
-      const position = billboardState(bb)?.position;
-      if (icao24 === flightState._trackedIcao || !position) continue;
+    const icons = flightState._icons;
+    const tau = parts.icons._displayTau();
+    for (let row = 0; row < icons.count; row++) {
+      const icao24 = icons.idAt(row);
+      if (icao24 === flightState._trackedIcao) continue;
+      const position = icons.position(row, tau, flightState._scratchCockpitPos);
      distancesSquared.push([
        icao24,
        Cesium.Cartesian3.distanceSquared(
@@ -181,13 +183,10 @@ export function createTracking({
      parts.rendering._modelKeepDistM(),
    );
    flightState._cockpitNearContacts = next;
-    let presentationChanged = false;
-    for (const [icao24, bb] of flightState._billboards) {
-      if (previous.has(icao24) === next.has(icao24)) continue;
-      parts.rendering._applyFleetBillboardPresentation(icao24, bb);
-      presentationChanged = true;
-    }
-    if (presentationChanged) flightState._lastCamPoseSig = '';
+    for (const icao24 of previous)
+      if (!next.has(icao24)) parts.icons._applyIconPresentation(icao24);
+    for (const icao24 of next)
+      if (!previous.has(icao24)) parts.icons._applyIconPresentation(icao24);
  }

  /** Switch all current and future ambient contacts between silhouettes and cockpit pips. */
@@ -205,9 +204,9 @@ export function createTracking({
    if (flightState._modelCollection) flightState._modelCollection.show = true;
    flightState._trail?.setVisible(!next);
    if (flightState._trailHeadEntity) flightState._trailHeadEntity.show = !next;
-    for (const [icao24, bb] of flightState._billboards)
-      parts.rendering._applyFleetBillboardPresentation(icao24, bb);
-    flightState._lastCamPoseSig = '';
+    const icons = flightState._icons;
+    for (let row = 0; row < (icons?.count ?? 0); row++)
+      parts.icons._applyIconPresentation(icons.idAt(row));
    flightState._lastFleetTickMs = 0;
  }

@@ -319,8 +318,7 @@ export function createTracking({
    if (!flightState._trackedIcao || !flightState._viewer) return;
    const pos =
      parts.motion._trackedDisplayCached() ||
-      billboardState(flightState._billboards.get(flightState._trackedIcao))
-        ?.position;
+      parts.icons._iconPosition(flightState._trackedIcao);
    if (!pos) return;
    const projected = screenProjectedRotation(
      flightState._viewer.scene,
@@ -639,30 +637,9 @@ export function createTracking({
    const clearedIcao = flightState._trackedIcao;
    clearFocusTarget('flights', clearedIcao);

-    // Restore the original billboard appearance. The rotation is re-seeded from
-    // the tracked entity's last rendered rotation and a rotation pass is forced
-    // (_lastCamPoseSig below): the fleet billboard otherwise reappears with the
-    // STALE screen rotation it had when tracking began — up to a full
-    // ROTATION_REFRESH_MS of a wrong (possibly reversed) nose on release.
-    if (flightState._billboards.has(flightState._trackedIcao)) {
-      const bb = flightState._billboards.get(flightState._trackedIcao);
-      setBillboard(bb, 'show', true);
-      setBillboard(bb, 'width', 20);
-      setBillboard(bb, 'height', 20);
-      // Ground/military-aware restore (a plane untracked while taxiing must come
-      // back muted-gray at ground scale, not white at full scale).
-      bb.color = parts.rendering._fleetBillboardColor(flightState._trackedIcao);
-      setBillboard(
-        bb,
-        'scale',
-        parts.rendering._fleetBillboardScale(
-          flightState._trackedIcao,
-          flightState.records.data.get(flightState._trackedIcao)?.klass,
-        ),
-      );
-      setBillboard(bb, 'rotation', flightState._lastTrackedRotation);
-    }
-    flightState._lastCamPoseSig = ''; // force a fleet rotation pass on the next tick
+    // The nose the icon continues from (the shared _displayCourse entry), so
+    // release never flips it.
+    const trackedCourseDeg = flightState._displayCourse.get(clearedIcao);

    // Stop tracking and remove the entity. skipViewerUntrack: when ANOTHER layer just grabbed the
    // follow-camera, we tear down our own state but must NOT clear viewer.trackedEntity (the new owner
@@ -679,10 +656,14 @@ export function createTracking({
    parts.rendering._releaseTrackedModel();
    _resetTrackedSelectionState(); // the zoom band + load-failure budget belong to the selection we just dropped
    flightState._trackedIcao = null;
-    parts.rendering._applyFleetBillboardPresentation(
-      clearedIcao,
-      flightState._billboards.get(clearedIcao),
-    );
+    // Hand the contact back to its icon only now: settling floors a grounded
+    // contact, and while it still read as tracked its tracked model owned the
+    // visual, so the floor would have stepped aside.
+    if (flightState._icons?.has(clearedIcao)) {
+      flightState._icons.setShown(flightState._icons.row(clearedIcao), true);
+      parts.icons._settleIcon(clearedIcao, { fromCourseDeg: trackedCourseDeg });
+    }
+    parts.icons._applyIconPresentation(clearedIcao);
    clearTrackedSubjectContext('flights');
    _emitAwarenessEvent('gev:awareness-subject-cleared', {
      layerId: 'flights',
@@ -730,10 +711,7 @@ export function createTracking({
      pending.generation !== flightState._trackingIntentGeneration
    )
      return false;
-    if (
-      !flightState._billboardCollection?.show ||
-      !flightState._billboards.has(pending.id)
-    )
+    if (!flightState._icons?.show || !flightState._icons.has(pending.id))
      return false;
    flightState._pendingTrackingRestore = null;
    _trackFlight(pending.id, { origin: pending.origin });
@@ -837,42 +815,42 @@ export function createTracking({
      // an already-loaded model would otherwise linger with the billboard hidden.
      if (flightState._models.has(id) || flightState._modelPending.has(id))
        parts.rendering._releaseModel(id);
-      const bb = flightState._billboards.get(id);
-      if (bb && id !== flightState._trackedIcao) setBillboard(bb, 'show', true); // horizon cull re-asserts next tick
+      const row = flightState._icons?.row(id) ?? -1;
+      if (row >= 0 && id !== flightState._trackedIcao)
+        flightState._icons.setShown(row, true);
      if (id === flightState._trackedIcao) {
        parts.rendering._releaseTrackedModel();
        _syncTracked2dRotation();
      }
    }
-    const bb = flightState._billboards.get(id);
-    if (bb) parts.rendering._applyFleetBillboardPresentation(id, bb);
+    parts.icons._applyIconPresentation(id);
    if (id === flightState._trackedIcao) {
      _syncTrackedBillboardImage();
      _updateTrackedLabelModel(id);
    }
    flightState._viewer?.scene?.requestRender?.();
-    return flightState._billboards.has(id) || id === flightState._trackedIcao;
+    return flightState._icons?.has(id) || id === flightState._trackedIcao;
  }

  /** Re-image every converted contact this layer owns (IR style flip). */

  function _refreshTr3bForStyle() {
    for (const id of tr3bConvertedIds()) {
-      if (flightState._billboards.has(id) || id === flightState._trackedIcao)
+      if (flightState._icons?.has(id) || id === flightState._trackedIcao)
        _refreshTr3bContact(id);
    }
  }

-  /** Plausibility check anchored to the plane's billboard position (coarse is
+  /** Plausibility check anchored to the plane's icon position (coarse is
   *  fine here — this gates a LABEL, and it must not touch the tracked frame
   *  cache). Missing data → true (never hide what we can't judge). */

  function _routeIsPlausible(icao24, route) {
    const info = flightState.records.data.get(icao24);
-    const bb = flightState._billboards.get(icao24);
-    if (!info || !bb || !billboardState(bb).position) return true;
+    const position = parts.icons._iconPosition(icao24);
+    if (!info || !position) return true;
    const carto = Cesium.Cartographic.fromCartesian(
-      billboardState(bb).position,
+      position,
      Cesium.Ellipsoid.WGS84,
      flightState._scratchCarto,
    );
@@ -907,29 +885,42 @@ export function createTracking({
  function _trackFlight(icao24, { origin = 'programmatic' } = {}) {
    _clearTracking(false, { origin }); // switching planes — the new follow-camera takes over

-    const bb = flightState._billboards.get(icao24);
+    const icons = flightState._icons;
+    const row = icons?.row(icao24) ?? -1;
    const info = flightState.records.data.get(icao24);
-    if (!bb || !info) return;
+    if (row < 0 || !info) return;

+    // The tracked limiter continues from the nose the icon was drawn with, and
+    // the entity starts with the rotation the icon had on screen.
+    const tau = parts.icons._displayTau();
+    const iconPosition = icons.position(row, tau);
+    flightState._displayCourse.set(icao24, icons.course(row, tau));
    flightState._trackedIcao = icao24;
    _resetTrackedSelectionState(); // fresh selection: enter at the ENTER ceiling, full load-retry budget
    flightState._cachedDRFrame = -1;
-    flightState._lastTrackedRotation = billboardState(bb).rotation || 0;
+    flightState._lastTrackedRotation =
+      screenProjectedRotation(
+        flightState._viewer.scene,
+        iconPosition,
+        icons.course(row, tau),
+        0,
+      ) ?? 0;
    // Drop any fleet 3D model for this aircraft — the tracked entity now owns its visual (its
    // own billboard + model graphic), and the fleet tick skips the tracked icao, so a leftover
    // fleet model would be orphaned + double-rendered.
    parts.rendering._releaseModel(icao24);

-    // Hide the billboard — the tracked entity replaces it visually
-    setBillboard(bb, 'show', false);
+    // Hide the icon — the tracked entity replaces it visually
+    icons.setShown(row, false);

    // Helper: smoothed, per-frame-cached tracked position (see _trackedDisplayPosition —
    // one computation shared by the position/alignedAxis/rotation/trail-head callbacks,
-    // with discontinuity reconciliation). Falls back to the last billboard position when
+    // with discontinuity reconciliation). Falls back to the icon's position when
    // the aircraft has no fix.
    const getTrackedPosition = () =>
      parts.motion._trackedDisplayPosition(icao24) ||
-      billboardState(bb).position;
+      parts.icons._iconPosition(icao24) ||
+      iconPosition;

    // Dead-reckoning position property — smooth continuous motion between API updates.
    const positionProperty = new Cesium.CallbackProperty(() => {
@@ -1106,23 +1097,19 @@ export function createTracking({
   */

  function _onMilitaryActiveChange(active) {
-    if (!flightState._viewer || !flightState._billboardCollection) return;
+    const icons = flightState._icons;
+    if (!flightState._viewer || !icons) return;
    if (active) {
-      for (const [icao24, bb] of flightState._billboards) {
-        if (!isMilitaryIcao(icao24) || icao24 === flightState._trackedIcao)
-          continue;
-        flightState._billboardCollection.remove(bb);
-        flightState._billboards.delete(icao24);
-        parts.rendering._releaseModel(icao24); // military-suppression: drop any 3D model too
-        flightState.records.data.delete(icao24);
-        flightState._cullPositions.delete(icao24);
-        flightState._positionHistory.delete(icao24);
-        flightState._displayCourse.delete(icao24);
-        flightState._groundSnap.forget(icao24);
-        flightState.records.missingPolls.delete(icao24);
+      const suppressed = [];
+      for (let row = 0; row < icons.count; row++) {
+        const icao24 = icons.idAt(row);
+        if (isMilitaryIcao(icao24) && icao24 !== flightState._trackedIcao)
+          suppressed.push(icao24);
      }
-      flightState.feed._count = flightState._billboards.size;
-    } else if (flightState._billboardCollection.show) {
+      // Military-suppression: drop each duplicate with any 3D model too.
+      for (const icao24 of suppressed) parts.icons._forgetContact(icao24);
+      flightState.feed._count = icons.count;
+    } else if (icons.show) {
      // Fire-and-forget refresh; only while the layer is actually enabled.
      void flightsLayer.update(flightState._viewer);
    }
@@ -1212,25 +1199,12 @@ export function createTracking({
            return;
        }

-        // For BillboardCollection picks, the billboard may be at picked.primitive or picked.id
-        const billboard = picked.primitive;
-        if (
-          billboard &&
-          billboard.id &&
-          flightState._billboards.has(billboard.id)
-        ) {
+        // Icon picks carry the icao on picked.id; models carry it on the primitive.
+        const pickedIcao =
+          typeof picked.id === 'string' ? picked.id : picked.primitive?.id;
+        if (pickedIcao && flightState._icons?.has(pickedIcao)) {
          _cancelPendingTrackingRestore();
-          _trackFlight(billboard.id, { origin: 'user' });
-          return;
-        }
-        // Some CesiumJS versions surface the id as a string on picked.id instead
-        if (
-          picked.id &&
-          typeof picked.id === 'string' &&
-          flightState._billboards.has(picked.id)
-        ) {
-          _cancelPendingTrackingRestore();
-          _trackFlight(picked.id, { origin: 'user' });
+          _trackFlight(pickedIcao, { origin: 'user' });
          return;
        }
      }
@@ -702,7 +702,7 @@ test('the Display selector, voice schema and final stylesheet expose Cyber', ()
  assert.doesNotMatch(detection, /sonarActive \? 1 : 0/);
  assert.match(
    civilRendering,
-    /alpha: flightState\._irBoost \? 1 : treatment\.alpha/,
+    /alpha: flightState\._irBoost\s*\?\s*1\s*:\s*aircraftTreatmentAlpha\(/,
  );
  assert.match(
    militaryRendering,