| 1 | QX | Horizon Airlines, Inc. | ICAO: QXE, Callsign: Horizon Air, IATA Prefix: 481, Name changed to Horizon Air Industries, Inc. Founded in 1981. Commenced operations on 01 September 1981. | USA | AVCODES |
| 2 | QX | Transair, S.A. | Callsign: Transair-Suisse, | CH | AVCODES |
| 3 | QX | Horizon Air Industries, Inc. | ICAO: QXE, Callsign: Horizon Air, IATA Prefix: 481, Name changed from Horizon Airlines, Inc. Founded in 1981. Commenced operations on 01 September 1981. | USA | AVCODES |
| 4 | QXE | Horizon Airlines, Inc. | IATA: QX, Callsign: Horizon Air, IATA Prefix: 481, Name changed to Horizon Air Industries, Inc. Founded in 1981. Commenced operations on 01 September 1981. | USA | AVCODES |
| 5 | QXE | Horizon Airlines, Inc. | Callsign: Horizon Air, | USA | AVCODES |
| 6 | QXE | Horizon Air Industries, Inc. | IATA: QX, Callsign: Horizon Air, IATA Prefix: 481, Name changed from Horizon Airlines, Inc. Founded in 1981. Commenced operations on 01 September 1981. | USA | AVCODES |
| 7 | QXE | Horizon Air | IATA: QX | | ICAO1 |
| 8 | QXHU | HUBEI QIXING AUTO BODY CO., LTD. | | PRC | BIC |
| 9 | QXIC | QXI | | | SCAC4 |
| 10 | QXPS | QUALITY EXPRESS INC | | | SCAC4 |
| 11 | QXSI | QUANTUM5X SYSTEMS INC | | | SCAC4 |
| 12 | QXTI | QUIK X TRANSPORTATION, INC | | | SCAC3 |
| 13 | QXTI | QUIK X TRANSPORTATION INC | | | SCAC4 |
| 14 | QXTS | QUANTEX TECHNOLOGIES INC | | | SCAC4 |
| 15 | QXUS | QUALITY EXPRESS USA INC | | | SCAC4 |
| 16 | QXXP | QUICK XXPRESS DELIVERY INC | | | SCAC4 |
