| 1 | FSX | Flagship Express Services, Inc. | Callsign: Flag, | USA | AVCODES |
| 2 | FSX | Flagship Express Services | | | ICAO1 |
| 3 | FSX | National Car Co. | 1/1952-7/1954; eliminated 1/1956 | | NAKINA |
| 4 | FSX | National Car Co. | Jan-52 | | NRHS |
| 5 | FSX | NATIONAL CAR CO. | | | PWRC |
| 6 | FSXA | FIVE STAR TRANSPORTATION AMERICA LL | | | SCAC4 |
| 7 | FSXB | FOUR (4) S EXPRESS | | | SCAC4 |
| 8 | FSXC | FOUR STAR EXPRESS INC | | | SCAC4 |
| 9 | FSXH | FOSTER TRANSPORT INC | | | SCAC4 |
| 10 | FSXI | FAST STAR EXPRESS INC | | | SCAC4 |
| 11 | FSXL | FSX LLC | | | SCAC4 |
| 12 | FSXN | FASTEX TRANSPORT | | | SCAC4 |
| 13 | FSXO | FOSS TRANSPORTATION | | | SCAC4 |
| 14 | FSXP | FAST EXPRESS INC | | | SCAC3 |
| 15 | FSXR | FAST EXPRESS | | | SCAC3 |
| 16 | FSXR | FST TRANSPORT | | | SCAC4 |
| 17 | FSXS | FIRST EXPRESS | | | SCAC3 |
| 18 | FSXY | FORTRESS TRANSPORTATION INC | | | SCAC4 |
