| 1 | QA | Aerocaribe | ICAO: CBE, Callsign: Aerocaribe, IATA Prefix: 723, Founded in 1972. Name changed to Mexicana Click in July 2005. | MEX | AVCODES |
| 2 | QA | Alidair Cargo Ltd. | Name changed to Inter City Airlines | GB | AVCODES |
| 3 | QA | Inter City Airlines | ICAO: CIT, Callsign: Quebec Alpha, Ceased operations in August 1983. Name changed from Alidair | GB | AVCODES |
| 4 | QA | Starlight Airline STP, S.A. | ICAO: SLT, Callsign: Starlight Cargo, IATA Prefix: 321, | STP | AVCODES |
| 5 | QA | African Express Airways (Kenya) Limited | ICAO: AEK, Callsign: African Express, | EAK | AVCODES |
| 6 | QA | MexicanaClick | ICAO: CBE, Callsign: Click, IATA Prefix: 723, Ceased all operations on 28 August 2010. Name changed from Aerocaribe | MEX | AVCODES |
| 7 | QA | Cimber A/S | ICAO: CIM, Callsign: Cimber, Merged into CityJet during 2018. Founded on 15 May 2012. Commenced operations on 16 May 2012 | DK | AVCODES |
| 8 | QA | Queen Bilqis Airways | ICAO: QBA, Callsign: Bilqis, | YAR | AVCODES |
| 9 | QA&P | Quanah, Acme & Pacific Ry. Co. | 7/1923 | | NAKINA |
| 10 | QA&P | QUANAH, ACME & PACIFIC RWY. CO. | | | PWRC |
| 11 | QAC | Qatar Air Cargo | Callsign: Qatar Cargo, | Q | AVCODES |
| 12 | QAC | Qatar Air Cargo | | | ICAO1 |
| 13 | QACG | QUINCY AIR CARGO INC | | | SCAC3 |
| 14 | QACL | QUEST AIRCRAFT COMPANY LLC | | | SCAC4 |
| 15 | QADQ | QUAD CITY LEASING COMPANY INC | | | SCAC3 |
| 16 | QADT | QUAD TRANSPORTATION SERVICES LLC | | | SCAC4 |
| 17 | QAF | Qatar Amiri Flight | IATA: Q4, Callsign: Amiri, Designator Q4* recalled by IATA. | Q | AVCODES |
| 18 | QAF | Qatar Amiri Flight | Callsign: Amiri, Designator Q4* recalled by IATA. | Q | AVCODES |
| 19 | QAF | Qatar Amiri Flight | | | ICAO1 |
| 20 | QAFI | QUALITY AIR FORWARDING INC | | | SCAC4 |
| 21 | QAH | Quick Airways Holland B.V. | Callsign: Quick, | NL | AVCODES |
| 22 | QAH | Quick Airways Holland | | | ICAO1 |
| 23 | QAI | Conquest Air, Inc. | IATA: C4, Callsign: Chickpea, IATA Prefix: 340, | USA | AVCODES |
| 24 | QAJ | Quick Air Jet Charter GmbH | Callsign: Dagobert, | D | AVCODES |
| 25 | QAJ | Quick Air Jet Charter | | | ICAO1 |
| 26 | QALL | QUALLS OIL CO INC | | | SCAC4 |
| 27 | QALT | QUALITY TRANSPORTATION INC | | | SCAC3 |
| 28 | QALY | QUALITY TRANSPORT INC | | | SCAC3 |
| 29 | QANA | QANTAS AIRWAYS LTD | | | SCAC4 |
| 30 | QAP | (QA&P) Quanah, Acme & Pacific Ry. Co. | 7/1930-1/1980; eliminated 7/1981 | | NAKINA |
| 31 | QAP | Quanah, Acme & Pacific Ry. Co. | 4/38-1/80; eliminated 7/81 | | NRHS |
| 32 | QAP | QUANAH, ACME & PACIFIC RWY. CO. | | | PWRC |
| 33 | QAPE | QU'APPELLE APPALOOSA RANCH | | | SCAC4 |
| 34 | QAPI | QWEST AIR PARTS INC | | | SCAC4 |
| 35 | QAQ | Qurinea Air Service | Callsign: Qurinea Air, | LAR | AVCODES |
| 36 | QAQ | Qurinea Air Service | | | ICAO1 |
| 37 | QAQL | QUICK AND QUALITY LOGISTICS INC | | | SCAC4 |
| 38 | QARX | QUEEN ANNE'S RAILROAD TOURIST / DINNER TRAIN OPERATOR | | | PWRC |
| 39 | QAS | Quisqueya Airlines, S.A. | Callsign: Quisqueya, | RH | AVCODES |
| 40 | QAS | Quisqueya Airlines | | | ICAO1 |
| 41 | QASW | Q ARION SHIPPING LTD | | | SCAC4 |
| 42 | QAT | Aero Taxi | Callsign: Air Quasar, | CDN | AVCODES |
| 43 | QAT | Aero Taxi | | | ICAO1 |
| 44 | QATA | QATAR AIRWAYS | | | SCAC4 |
| 45 | QATI | QAT INC | | | SCAC3 |
| 46 | QATL | QUADRA TRANSPORT LTD | | | SCAC3 |
| 47 | QATP | QUALITY TRANSPORT, INC | | | SCAC3 |
| 48 | QATP | QUALITY TRANSPORT INC | | | SCAC4 |
| 49 | QATR | QATAR SHIPPING COMPANY Q S C | | | SCAC4 |
| 50 | QATT | QUALITY AUTO TRANSPORT | | | SCAC3 |
| 51 | QATY | QUALITY HOT MIX TRUCKING INC | | | SCAC4 |
| 52 | QAUQ | QUOTE A UNQUOTE TRANSPORTATION INC | | | SCAC3 |
| 53 | QAV | QA Aviation s.r.o. | Callsign: Quiet Aviation, ICAO designator changed from QNR w.e.f. 01 June 2022. | CZ | AVCODES |
| 54 | QAWC | QUALITY WAREHOUSE CO INC | | | SCAC3 |
| 55 | QAZ | Qazaq Air Joint Stock Company | IATA: IQ, Callsign: Samruk, | KZ | AVCODES |
