| 101 | QBC | Quebec Aviation Ltd. | Callsign: Inter, ICAO callsign changed to Quebec Aviation | CDN | AVCODES |
| 102 | QBC | Quebec Aviation Ltd. | Callsign: Quebec Aviation, ICAO callsign changed from Inter | CDN | AVCODES |
| 103 | QBCR | QB CORPORATION | | | SCAC3 |
| 104 | QBCU | CUBICFARM MANUFACTURING CORP | | CDN | BIC |
| 105 | QBD | Qingdao Air Express General Aviation Co., Ltd. | Callsign: Seagull Air, | PRC | AVCODES |
| 106 | QBEC | QUEBEC SHIPPING CORP | | | SCAC3 |
| 107 | QBLU | QBEX LOGISTICS BV | | NL | BIC |
| 108 | QBMO | QUEEN BEE MOVERS | | | SCAC3 |
| 109 | QBSA | QUALITY BATTERY SYSTEMS | | | SCAC4 |
| 110 | QBSC | QUEENSBRIDGE SHIPPING CORP MONROVIA | | | SCAC3 |
| 111 | QBT | Quincy Bay Terminal Co. | added 10/1992; 1/1994-7/2000; eliminated 10/2001; 7/2005 | | NAKINA |
| 112 | QBT | Quincy Bay Terminal Co. | added 10/92; 1/94-7/2000 | | NRHS |
| 113 | QBT | QUINCY BAY TERMINAL COMPANY | | | PWRC |
| 114 | QBT | Quincy Bay Terminal | | | RSRV |
| 115 | QBTI | QUISENBERRY TRUCKING INC | | | SCAC3 |
| 116 | QBTI | QB TRANSPORT INC | | | SCAC4 |
| 117 | QBUS | Q-Bus Nahverkehrsgesellschaft mbH | City: Ballenstedt | D | TRAFFIC |
| 118 | QBUZ | Qbuzz | | NL | TRAFFIC |
| 119 | QBXI | QUEBEC EXPRESS INC | | | SCAC3 |
| 120 | QBXU | CHS CONTAINER HANDEL GMBH | | D | BIC |
| 121 | QBXU | CHS CONTAINER HANDEL GMBH | | | SCAC4 |
| 122 | QBZ | Qbuzz | | NL | TRAFFIC |
| 123 | QC | Aviation Quebec Labrador LTEE | ICAO: QLA, Callsign: Quebec Labrador, Designator QC recalled by IATA. IATA designator changed from JT* | CDN | AVCODES |
| 124 | QC | Air Zaire | ICAO: AZR, Callsign: Air Zaire, | ZAR | AVCODES |
| 125 | QC | Air Corridor | ICAO: CRD, Callsign: Air Corridor, Designator QC reinstated by IATA | MOC | AVCODES |
| 126 | QC | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 127 | QC | CP Rail System (Canadian Pacific Ltd.) | added 7/1994; eliminated 1/1997 | | NAKINA |
| 128 | QC | Quebec Central Ry. (Co.) | 8/1920-10/1957; 1/1975; added 10/1979; 1/1980-1/1994; eliminated 7/1994 | | NAKINA |
| 129 | QC | Quebec Central Ry. | 4/38-10/57 | | NRHS |
| 130 | QC | Quebec Central Ry. Co. | 1/75-1/94; eliminated 7/94 | | NRHS |
| 131 | QC | CP Rail System (Canadian Pacific Ltd.) | added 7/94; eliminated 1/97 | | NRHS |
| 132 | QC | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | | NRHS |
| 133 | QC | CP RAIL [QUEBEC CENTRAL RY] | | | PWRC |
| 134 | QC | Quebec Central Railway | | | RSRV |
| 135 | QC | Quebec Central Railway Company | | CDN | TRAFFIC |
| 136 | QCAF | QUEEN CITY AIR FREIGHT | | | SCAC3 |
| 137 | QCAF | QUEEN CITY AIR FREIGHT | | | SCAC4 |
| 138 | QCAI | Q CARRIERS INC | | | SCAC3 |
| 139 | QCBH | QCB SHIPPING | | | SCAC4 |
| 140 | QCC | Qwest Commuter Corporation | Callsign: Qwest Air, | USA | AVCODES |
| 141 | QCC | Qwest Commuter Corporation | | | ICAO1 |
| 142 | QCCC | QUICK/CARE CORPORATION | | | SCAC3 |
| 143 | QCCC | QUICKPICK.COM LLC | | | SCAC4 |
| 144 | QCCI | QUAKER CITY CHEMICALS INC | | | SCAC4 |
| 145 | QCCR | QUAL CON CONCRETE CONTRACTORS | | | SCAC4 |
| 146 | QCCX | General Electric Rail Services Corp. | added 10/2009 | | NAKINA |
| 147 | QCCX | Equistar Chemicals, LP | added 4/1998; 7/2000-7/2005; eliminated 10/2009 | | NAKINA |
| 148 | QCCX | Quantum Chemical Corp., USI Division | eliminated 4/1998 | | NAKINA |
| 149 | QCCX | Trancisco Leasing Co. | added 10/1996; eliminated 1/1997 | | NAKINA |
| 150 | QCCX | Quantum Chemical Corp. | added 1/1997 | | NAKINA |
| 151 | QCCX | Trancisco Leasing Co. | added 10/96; eliminated 1/97 | | NRHS |
| 152 | QCCX | Quantum Chemical Corp. | added 1/97 | | NRHS |
| 153 | QCCX | Quantum Chemical Corp., USI Division | eliminated 4/98 | | NRHS |
| 154 | QCCX | Equistar Chemicals, LP | added 4/98; 7/2000 | | NRHS |
| 155 | QCCX | EQUISTAR CHEMICALS LP [QUANTUM CHEMICAL CORP.] (TRANCISCO LEASING) | | | PWRC |
| 156 | QCCX | Quantum Chemical Corporation | | | RSRV |
| 157 | QCCX | EQUISTAR CHEMICALS LP | | | SCAC4 |
| 158 | QCDS | QUALITY COURIER & DELIVERY SERVICE | | | SCAC3 |
| 159 | QCEP | QUIVAS CARGO EXPRESS | | | SCAC4 |
| 160 | QCFL | QUIK CHEK FUELS | | | SCAC4 |
| 161 | QCGU | Quest Capital Group | | | RSRV |
| 162 | QCGU | QUEST CAPITAL GROUP LLC | | | SCAC4 |
| 163 | QCHM | QUALITY CRAFT HOMES | | | SCAC4 |
| 164 | QCIC | QUALITY CARTAGE INCORPORATED | | | SCAC3 |
| 165 | QCIN | QUALITY COURIER INC | | | SCAC3 |
| 166 | QCIY | QUEEN CITY INC | | | SCAC4 |
| 167 | QCL | Air Class Lineas Aereas (Aerovip Ltda) | IATA: QD, Callsign: Acla, Founded in 1996. Commenced operations in 1997. | ROU | AVCODES |
| 168 | QCL | AeroVIP S.A. (Air Class) | IATA: VZ, Callsign: Acla, IATA Prefix: 762, Founded in 1996. Commenced operations in 1997. Name changed to Air Express S.A. d/b/a Air Class Lineas Aereas. | ROU | AVCODES |
| 169 | QCL | Air Express S.A. d/b/a Air Class Lineas Aereas | IATA: VZ, Callsign: Acla, IATA Prefix: 762, Founded in 1996. Commenced operations in 1997. Name changed from AeroVIP S.A. (Air Class). | ROU | AVCODES |
| 170 | QCL | Air Class Lineas Aereas | IATA: QD | | ICAO1 |
| 171 | QCLH | QUAIL CREEK LIVESTOCK HAULING INC | | | SCAC4 |
| 172 | QCLI | QUALITY COACH LINES INC | | | SCAC3 |
| 173 | QCLL | QUICK COACH LINES LTD | | | SCAC3 |
| 174 | QCLL | QUICK COACH LINES LTD | | | SCAC4 |
| 175 | QCM | Quebec Cartier Mining Railway | | CDN | TRAFFIC |
| 176 | QCMF | QUINTE CANVAS MANUFACTURING | | | SCAC4 |
| 177 | QCMH | Q C MOBILE HOMES INC | | | SCAC3 |
| 178 | QCMS | QUEEN CITY MOVING & STORAGE CO | | | SCAC3 |
| 179 | QCR | Quebec Central Ry. Co. | 7/2005 | | NAKINA |
| 180 | QCR | QUEBEC CENTRAL RWY. CO. | | | PWRC |
| 181 | QCR | Quebec Central Railway | | | RSRV |
| 182 | QCR | QUEBEC CENTRAL RAILWAY COMPANY | | | SCAC4 |
| 183 | QCR | Quebec Central Rail | | CDN | TRAFFIC |
| 184 | QCRS | QUALITY OF CALIFORNIA RELOCATION SE | | | SCAC3 |
| 185 | QCSE | QUICK COURIER SERVICES | | | SCAC4 |
| 186 | QCSF | QUICK CSF INC | | | SCAC4 |
| 187 | QCSI | QUALITY CONTAINER SERVICES INC | | | SCAC3 |
| 188 | QCSI | QUALITY CONTAINER SERVICES INC | | | SCAC4 |
| 189 | QCSL | QUALITY CONSOLIDATORS LTD | | | SCAC3 |
| 190 | QCSV | QUALITY COURIER SERVICE | | | SCAC3 |
| 191 | QCSY | Q C SYSTEMS OF LANCASTER INC | | | SCAC3 |
| 192 | QCTA | QUARTER CIRCLE 13 TRANSPORTATION | | | SCAC4 |
| 193 | QCTD | QUALITY CONSTRUCTION (TRUCKING DIVI | | | SCAC4 |
| 194 | QCTH | QUETOP CORPORATION, THE | | | SCAC4 |
| 195 | QCTS | QUEEN CITY TRAFFIC SERVICE INC | | | SCAC3 |
| 196 | QCTY | QUEEN CITIES | | | SCAC3 |
| 197 | QCWC | QUEEN CITY WAREHOUSE CORP | | | SCAC3 |
| 198 | QCX | Quemahoning Coal Co. | 8/1920-7/1923 | | NAKINA |
| 199 | QCX | QUEMAHONING COAL CO. | | | PWRC |
| 200 | QCXU | QUALITY CARRIERS | | USA | BIC |
