| 1 | QT | Transportes Aereos Mercantiles Panamericanos S.A., (TAMPA) | ICAO: TPA, Callsign: Tampa, IATA Prefix: 729, Name changed to Transportes Aereos Mercantiles Panamericanos S.A., (TAMPA) t/a Avianca Cargo w.e.f. 28 May 2013. | CO | AVCODES |
| 2 | QT | Regional Air PTY Ltd. | | PNG | AVCODES |
| 3 | QT | Inter City Airlines | Ceased operations on 01 August 1983. Name changed from Alidair | GB | AVCODES |
| 4 | QT | Aer Turas Teoranta | ICAO: ATT, Callsign: Quebec Tango, | IRL | AVCODES |
| 5 | QT | Transportes Aereos Mercantiles Panamericanos S.A., (TAMPA) t/a Avianca Cargo | ICAO: TPA, Callsign: Tampa, IATA Prefix: 729, Name changed from Transportes Aereos Mercantiles Panamericanos S.A., (TAMPA) w.e.f. 28 May 2013. | CO | AVCODES |
| 6 | QT | Queens Transit | City: New York | US-NY | TRAFFIC |
| 7 | QTAC | QUEENS TRUCKING AND CONSTRUCTION IN | | | SCAC4 |
| 8 | QTAP | QUALITY TRANSPORTATION INC | | | SCAC3 |
| 9 | QTAP | QUEST TRANSPORT LLC | | | SCAC4 |
| 10 | QTCC | QUALITY CONTRACT CARRIERS INC | | | SCAC3 |
| 11 | QTCI | QUEST TRANSPORTATION COMPANY INC | | | SCAC3 |
| 12 | QTCL | QUICK TURN CARGO LLC | | | SCAC4 |
| 13 | QTCO | QUALITY TRADING CO L L C | | | SCAC4 |
| 14 | QTCR | QUIVICAN TRUCKING CORP | | | SCAC4 |
| 15 | QTCU | QT CONTAINER LINE (HK) LIMITED | | HK | BIC |
| 16 | QTEC | QUALTECH INC | | | SCAC4 |
| 17 | QTEF | QUICK TRIP EXPRESS FREIGHT SERVICE | | | SCAC4 |
| 18 | QTFF | QUINTANA, TONY FREIGHT FORWARDERS I | | | SCAC3 |
| 19 | QTI | Quaboag Transfer | | CDN | TRAFFIC |
| 20 | QTIA | QUALITY TRANSPORT OF IOWA INC | | | SCAC3 |
| 21 | QTIB | QUEEN TRANSPORT INC | | | SCAC4 |
| 22 | QTIC | Q T INC | | | SCAC3 |
| 23 | QTIC | Q T INC | | | SCAC4 |
| 24 | QTIG | QUALITY TRUCKING INC | | | SCAC3 |
| 25 | QTII | Q T I | | | SCAC4 |
| 26 | QTIM | QC TECHNIQUES INC | | | SCAC4 |
| 27 | QTIN | QUALITY TRUCKING INC | | | SCAC3 |
| 28 | QTIN | QUALITY TRUCKING INC | | | SCAC4 |
| 29 | QTIQ | QUORUM TECHNOLOGIES INC | | | SCAC4 |
| 30 | QTJA | QUINTANA TRUJILLO, JOSE ANTONIO | | | SCAC4 |
| 31 | QTJL | QUIROZ TRUJILLO, JOSE LUIS | | | SCAC4 |
| 32 | QTKI | QUALITY TRUCKING INC | | | SCAC4 |
| 33 | QTKL | QUALITY TRUCK LINES INC | | | SCAC3 |
| 34 | QTLD | QUEENSWAY TANK LINES INC | | | SCAC3 |
| 35 | QTLI | QUALITY TRANSPORTATION & LOGISTICS | | | SCAC4 |
| 36 | QTLJ | QUALITY TRANSPORTATION LLC | | | SCAC4 |
| 37 | QTLL | QUALITY TRANS LOGISTICS LLC | | | SCAC4 |
| 38 | QTLT | QUIETT TRANSPORTATION LTD | | | SCAC3 |
| 39 | QTLY | QUEEN TRANSPORTATION LLC | | | SCAC4 |
| 40 | QTMU | QUANTUM FUEL SYSTEM LLC | | USA | BIC |
| 41 | QTNB | QUALITY TRANSPORTATION SERVICES (N | | | SCAC4 |
| 42 | QTNH | QUINTAN HOLDINGS LTD | | | SCAC3 |
| 43 | QTNM | QUALTIY TRACTOR & MACHINERY INC | | | SCAC3 |
| 44 | QTNV | QUALITY TRANSPORTATION SERVICES OF | | | SCAC3 |
| 45 | QTPC | QUINTANA TRANSPORTATION CO | | | SCAC4 |
| 46 | QTPI | Q TRANSPORT INC | | | SCAC4 |
| 47 | QTPL | QUICK TRANSPORT LLC | | | SCAC4 |
| 48 | QTPS | QUALITY TRANSPORTATION SERVICES INC | | | SCAC4 |
| 49 | QTR | Qatar Airways (W.L.L.) | IATA: QR, Callsign: Qatari, IATA Prefix: 157, Name changed to Qatar Airways Group Q.C.S.C. | Q | AVCODES |
| 50 | QTR | Qatar Airways Group Q.C.S.C. | IATA: QR, Callsign: Qatari, IATA Prefix: 157, Name changed from Qatar Airways (W.L.L.) | Q | AVCODES |
| 51 | QTR | Qatar Airways | IATA: QR | | ICAO1 |
| 52 | QTR | Qatar Airways | | Q | TRAFFIC |
| 53 | QTRB | QURAISHI TRUCKING | | | SCAC4 |
| 54 | QTRC | QUEENS TRUCKING | | | SCAC4 |
| 55 | QTRI | QUALI-T-RUCK SERVICE, INC | | | SCAC3 |
| 56 | QTRI | QUALI-T-RUCK SERVICE INC | | | SCAC4 |
| 57 | QTRK | QUALITY TRUCKING | | | SCAC4 |
| 58 | QTRP | QUINT TRANSPORT INC | | | SCAC3 |
| 59 | QTRP | QUIROGAS TRANSPORT | | | SCAC4 |
| 60 | QTRQ | QT TRANSPORT | | | SCAC4 |
| 61 | QTRT | QUIJANOS TRANSPORT | | | SCAC4 |
| 62 | QTSA | QUALITY TRANSPORTATION SERVICES INC | | | SCAC4 |
| 63 | QTSC | QUALITY TRANSPORT SERVICE LTD | | | SCAC3 |
| 64 | QTSC | QTS INC | | | SCAC4 |
| 65 | QTSI | QUALITY TRANSPORTATION SERVICES INC | | | SCAC3 |
| 66 | QTSI | QUALITY TRANSPORTATION SERVICES INC | | | SCAC4 |
| 67 | QTSJ | QUALITY TRANSPORT SERVICES OF JACKS | | | SCAC3 |
| 68 | QTSJ | QUALITY TRANSPORT SERVICES OF JACKS | | | SCAC4 |
| 69 | QTSO | QUALITY TRANSFER & STORAGE CO | | | SCAC4 |
| 70 | QTSR | QUALITY TRANSPORTATION SERVICES INC | | | SCAC4 |
| 71 | QTSV | QUALITY TRANSPORTATION SERVICES INC | | | SCAC3 |
| 72 | QTTI | QUALITY TOUR TRANSPORT INC | | | SCAC3 |
| 73 | QTTR | QUALITY TRUCK & TRAILER REPAIR | | | SCAC3 |
| 74 | QTTR | QUALITY LOGISTICS INC | | | SCAC4 |
| 75 | QTTX | TTX Co. | added 1/1992; 1/1994-7/2005 | | NAKINA |
| 76 | QTTX | Trailer Train Co. | added 10/1964; 7/1965-10/1966; eliminated 10/1967; 4/1970; eliminated 7/1972; 1/1975-1/1980; added 7/1991; eliminated 1/1992 | | NAKINA |
| 77 | QTTX | Trailer Train Co. | added 10/1964 | | NAKINA |
| 78 | QTTX | Trailer Train Co. (FMS flat cars specially equipped to provide for loading of agricultural equipment) | 7/1965-10/1966; eliminated 10/1967 | | NAKINA |
| 79 | QTTX | Trailer Train Co. (same as OTTX) | 4/1970; eliminated 7/1972 | | NAKINA |
| 80 | QTTX | Trailer Train Co. (no definition) | 1/1975-1/1980 | | NAKINA |
| 81 | QTTX | Trailer Train Co./TTX Co. (heavy capacity special type flats AAR mechanical designations FD and FM ranging in capacity from 110-ton to 245-ton of various lengths) | added 7/1991; 10/1991-1/1994 | | NAKINA |
| 82 | QTTX | TTX Co. (heavy capacity special type flats AAR mechanical designations FD and FM ranging in capacity from 105-ton to 370-ton of various lengths, equipped with end of car cush.) | 7/2000 | | NAKINA |
| 83 | QTTX | Trailer Train Co. | Jul-65 | | NRHS |
| 84 | QTTX | Trailer Train Co. (FMS flat cars specially equipped to provide for loading of agricultural equipment) | 10/66; eliminated 10/67 | | NRHS |
| 85 | QTTX | Trailer Train Co. | Apr-70 | | NRHS |
| 86 | QTTX | Trailer Train Co. (no definition) | 1/75-1/80 | | NRHS |
| 87 | QTTX | Trailer Train Co. | added 7/91; eliminated 1/92 | | NRHS |
| 88 | QTTX | TTX Co. | added 1/92 | | NRHS |
| 89 | QTTX | TTX Co. (heavy capacity special type flats AAR mechanical designations FD and FM ranging in capacity from 110-ton to 245-ton of various lengths) | Jan-94 | | NRHS |
| 90 | QTTX | TTX Co. (heavy capacity special type flats AAR mechanical designations FD and FM ranging in capacity from 105-ton to 370-ton of various lengths, equipped with end of car cush.) | Jul-00 | | NRHS |
| 91 | QTTX | TTX CO. | | | PWRC |
| 92 | QTTX | TTX Corporation | | | RSRV |
| 93 | QTTX | TTX COMPANY | | | SCAC4 |
| 94 | QTUI | Q2U INC | | | SCAC4 |
| 95 | QTUK | Q TRUCKING INC | | | SCAC3 |
| 96 | QTUM | QUANTUM TRANSPORTATION LLC | | | SCAC4 |
| 97 | QTX | Quantex Environmental, Inc. | Callsign: Air Quantex, | CDN | AVCODES |
| 98 | QTX | Quantex Environmental | | | ICAO1 |
| 99 | QTX | General American Transportation Corp. | 7/1937-1/1943 | | NAKINA |
| 100 | QTX | Quaker City Tank Line (General American Tank Car Corp.) | 7/1935 | | NAKINA |
