| 1 | XA | ARINC (Aeronautical Radio, Inc.) | ICAO: XAA, Callsign: Rockfish, Comms org for airline industry | USA | AVCODES |
| 2 | XAA | ARINC (Aeronautical Radio, Inc.) | IATA: XA, Callsign: Rockfish, Comms org for airline industry | USA | AVCODES |
| 3 | XAA | Aeronautical Radio Inc | | | ICAO1 |
| 4 | XAAK | XAAK TRANSPORT INC | | | SCAC4 |
| 5 | XAB | Xabre Aerolineas, S.A. de C.V. | Callsign: Aero Xabre, | MEX | AVCODES |
| 6 | XAB | Xabre Aerolineas | | | ICAO1 |
| 7 | XAC | Air Charter World | | USA | AVCODES |
| 8 | XAC | Air Charter World | | | ICAO1 |
| 9 | XACU | ALPSCONTAINER | | D | BIC |
| 10 | XAD | Certified Aircraft Dispatch, Inc. | | USA | AVCODES |
| 11 | XAD | Certified Air Dispatch | | | ICAO1 |
| 12 | XAE | Xair Brno | Callsign: Aura, | CZ | AVCODES |
| 13 | XAF | Executive Air Fleet | | USA | AVCODES |
| 14 | XAF | Executive Air Fleet | | | ICAO1 |
| 15 | XAGU | XI'AN INTERNATIONAL PORT MULTIMODAL TRANSPORTATION CO.,LTD | | PRC | BIC |
| 16 | XAH | Executive Aircraft Services | | GB | AVCODES |
| 17 | XAH | Executive Aircraft Services | | | ICAO1 |
| 18 | XAI | Apex Air Co., Ltd. | Callsign: Pex Air, | PRC | AVCODES |
| 19 | XAK | Airkenya Express Ltd. | IATA: QP, IATA Prefix: 853, Name changed from Airkenya Aviation Ltd. d/b/a Regional Air. Formerly Airkenya Aviation Ltd. | EAK | AVCODES |
| 20 | XAK | Airkenya Express Ltd. | IATA: P2, IATA Prefix: 853, IATA Designator changed from QP. Designator reinstated by P2 IATA. Name changed from Airkenya Aviation Ltd. d/b/a Regional Air. Formerly Airkenya Aviation Ltd. | EAK | AVCODES |
| 21 | XAK | Airkenya | | | ICAO1 |
| 22 | XAL | Aerovias Xalitic. S.A. de C.V. | Callsign: Xalitic, | MEX | AVCODES |
| 23 | XAL | Airlines of Tasmania Pty Ltd. | ICAO designator changed to ATM | AUS | AVCODES |
| 24 | XAM | AMR Services Corp | Callsign: Alliance, | USA | AVCODES |
| 25 | XAM | AMR Services Corporation | | | ICAO1 |
| 26 | XANS | XAN SYSTEMS INC | | | SCAC4 |
| 27 | XANT | XPEDX TRANSPORTATION RICHMOND (DIV | | | SCAC4 |
| 28 | XANU | PETRO KIMIA NEGIN CO | | | SCAC4 |
| 29 | XAO | Airline Operations Services | | USA | AVCODES |
| 30 | XAO | Airline Operations Services | | | ICAO1 |
| 31 | XAP | Direct Air, Inc. d/b/a Midway Connection | Callsign: Mid-Town, | USA | AVCODES |
| 32 | XAP | Direct Air, Inc. | Callsign: Air Direct, | USA | AVCODES |
| 33 | XAP | Midway Connection | | | ICAO1 |
| 34 | XAPU | XI'AN FREE TRADE PORT CONSTRUCTION AND OPERATION CO.,LTD. | | PRC | BIC |
| 35 | XAR | PT. Travel Express Aviation Services d/b/a Xpress Air | IATA: XN, Callsign: Travel Express, Name change from PT. Travel Express Aviation Services d/b/a Express Air during 2012. | RI | AVCODES |
| 36 | XAR | PT. Travel Express Aviation Services d/b/a Express Air | IATA: XN, Callsign: Travel Express, Name changed to PT. Travel Express Aviation Services d/b/a xpressair during 2012. | RI | AVCODES |
| 37 | XAR | Travel Express Aviation Services | | | ICAO1 |
| 38 | XARU | OXYGEN & ARGON WORKS LTD | | IL | BIC |
| 39 | XAS | PHH Aviation Systems, Inc. | | USA | AVCODES |
| 40 | XAS | PHH Aviation System | | | ICAO1 |
| 41 | XAT | AT And T Aviation Division | | USA | AVCODES |
| 42 | XAT | AT and T Aviation Division | | | ICAO1 |
| 43 | XAU | Aerolink Uganda Limited | IATA: A8, Designator A8* recalled by IATA | EAU | AVCODES |
| 44 | XAU | Aerolink Uganda Limited | IATA: A8, Designator A8* reinstated by IATA | EAU | AVCODES |
| 45 | XAV | Aviaprom Enterprises | Callsign: Aviaprom, | RUS | AVCODES |
| 46 | XAV | Aviaprom Enterprises | | | ICAO1 |
| 47 | XAW | Zoom Airways Limited | IATA: 3Z, | BD | AVCODES |
| 48 | XAX | Airx Limited t/a Lecocqs.com | Callsign: Blue Island, Name changed to Airx Limited t/a Rockhopper | GB | AVCODES |
| 49 | XAX | Airx Limited t/a Rockhopper | Callsign: Blue Island, Name changed to Airx Limited t/a Blue Islands. Name changed from Airx Limited t/a Lecocqs.com | GB | AVCODES |
| 50 | XAX | Airasia X Berhad d/b/a Airasia X | IATA: D7, Callsign: Xanadu, IATA Prefix: 843, Name changed from Fly Asian Express Sdn Bhd | MAL | AVCODES |
| 51 | XAX | AirAsia X | | MAL | TRAFFIC |
