fix(tools): read an airline only from a callsign of seven characters or fewer

ICAO flight-plan Item 7 caps aircraft identification at seven characters, so
the flight number after the designator is one to four characters, not five.
Philippine RP-C1234 and Cuban CU-T1240 registrations read like a designator
plus a flight number once the hyphen is dropped; they now count as unknown.
Cubana's CUB123 still counts as CUB.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/tools/queries/aviation.js

@@ -44,15 +44,17 @@ const GROUP_LABELS = Object.freeze({
 
 /**
  * The ICAO airline designator a callsign flies under: three letters, then a
- * flight number that starts with a digit (SWA1234, UAL12A, BAW1). Registrations
- * used as callsigns (N123AB, GABCD) have no designator.
+ * flight number that starts with a digit, seven characters at most (SWA1234,
+ * UAL12A, BAW1). Registrations used as callsigns (N123AB, GABCD) have no
+ * designator; Philippine RP-C1234 and Cuban CU-T1240, which read like one
+ * without their hyphen, are excluded too.
  */
 export function airlineDesignator(callsign) {
-  const match = /^([A-Z]{3})\d[0-9A-Z]{0,4}$/.exec(
-    String(callsign ?? '')
-      .trim()
-      .toUpperCase(),
-  );
+  const text = String(callsign ?? '')
+    .trim()
+    .toUpperCase();
+  if (/^(?:RPC|CUT)\d{4}$/.test(text)) return null;
+  const match = /^([A-Z]{3})\d[0-9A-Z]{0,3}$/.exec(text);
   return match ? match[1] : null;
 }
 

src/tools/queries/aviation.test.mjs

@@ -516,6 +516,10 @@ test('an airline designator is read from an ICAO flight callsign only', () => {
     ['GABCD', null],
     ['SWA', null],
     ['SWAX123', null],
+    ['SWA12345', null],
+    ['RPC1234', null],
+    ['CUT1240', null],
+    ['CUB123', 'CUB'],
     ['', null],
     [null, null],
   ])