| 301 | QH | Air Florida | ICAO: FLA, Callsign: Palm, Ceased operations on 03 July 1984. | USA | AVCODES |
| 302 | QH | Aircompany "Kyrgyzstan" | ICAO: LYN, Callsign: Altyn Avia, Name changed to OJSC Air Kyrgyzstan. Name changed from Altyn Air Airlines | KS | AVCODES |
| 303 | QH | Bamboo Airways Joint Company Limited | ICAO: BAV, Callsign: Bamboo, IATA Prefix: 926, | VN | AVCODES |
| 304 | QHAR | QUALITY HARDWOOD PRODUCTS INC | | | SCAC4 |
| 305 | QHCT | QUALITY HAY CO TRANSPORTATION INC | | | SCAC3 |
| 306 | QHD | Meregrass, Inc. | Callsign: Quahadi, | USA | AVCODES |
| 307 | QHGF | QUALITY HOUSEHOLD GOODS FORWARDERS | | | SCAC3 |
| 308 | QHIA | QUALITY HAULERS INC | | | SCAC4 |
| 309 | QHII | QUICKSILVER HOTSHOTS INC | | | SCAC4 |
| 310 | QHSD | QUALITY HAY SERVICE DIVISION | | | SCAC3 |
| 311 | QHSS | QINGDAO HUIQUAN SHIPPING COMPANY | | | SCAC4 |
| 312 | QHTE | QUARTER HORSE TRUCKING | | | SCAC4 |
| 313 | QI | Cimber Air A/S | ICAO: CIM, Callsign: Cimber, IATA Prefix: 647, Namce changed to Cimber A/S / Cimber Sterling. ICAO designator changed from DQI | DK | AVCODES |
| 314 | QI | Cimber Air, Sonderjyllands Flyveselskab | ICAO: DQI, Callsign: Cimber, IATA Prefix: 647, ICAO designator changed to CIM | DK | AVCODES |
| 315 | QI | Cimber Sterling A/S | ICAO: CIM, Callsign: Cimber, IATA Prefix: 647, Ceased Operations and filed for bankruptcy on 03 May 2012. Namce changed from Cimber Air A/S. ICAO designator changed from DQI | DK | AVCODES |
| 316 | QI | Ibom Airlines Limited | ICAO: IAN, Callsign: Ibom, | WAN | AVCODES |
| 317 | QIBU | HAPAG LLOYD A.G | | D | BIC |
| 318 | QIBU | UNITED ARAB SHIPPING CO SAG | | | SCAC4 |
| 319 | QIC | Aero Quick | | MEX | AVCODES |
| 320 | QID | United States Air Force 100th Air Refueling Wing | Callsign: Quid, RAF Mildenhall | USA | AVCODES |
| 321 | QID | USAF 100th Air Refuelling Wing | | | ICAO1 |
| 322 | QIIC | QUANTUM INDUSTRIES INC | | | SCAC4 |
| 323 | QIKA | QUIKRETE OF SOUTHERN CAL LLC | | | SCAC4 |
| 324 | QIKD | QUICK DELIVERY INC | | | SCAC3 |
| 325 | QIKD | QING DAO JMS LOGISTICS SERVICE CO L | | | SCAC4 |
| 326 | QIKR | QUIK TRUCKING CO | | | SCAC3 |
| 327 | QIKS | QUICKSILVER TRANS-TPT CLEARING | | | SCAC3 |
| 328 | QIKS | QUIJADA GARCIA, JUAN FRANCO | | | SCAC4 |
| 329 | QILC | QUINTANILLA INTERNATIONAL LLC | | | SCAC4 |
| 330 | QIMC | QUALITY INTERMODAL CORPORATION | | | SCAC3 |
| 331 | QIMU | TCS TRANS S.L. | | E | BIC |
| 332 | QIMU | QUIMITRAN INTERMODAL S L | | | SCAC4 |
| 333 | QIND | QRT INCORPORATED | | | SCAC4 |
| 334 | QINQ | QUINNS DELIVERY SERVICE INC | | | SCAC3 |
| 335 | QINT | QUESTAR INTERNATIONAL LTD | | | SCAC4 |
| 336 | QISB | QUIMICA IBEROAMERICANA SA DE CV | | | SCAC4 |
| 337 | QISS | QUALITY INTERNATIONAL | | | SCAC4 |
| 338 | QIT | Quebec Iron & Titanium | | CDN | TRAFFIC |
| 339 | QITR | QUICKDROP IMPOUNDING TOWING & RECOV | | | SCAC4 |
| 340 | QITX | QIT-Fer Et Titane | 7/2005 (not listed)( | | NAKINA |
| 341 | QITX | QIT-FER ET TITANE (QUEBEC IRON & TITANIUM) | | | PWRC |
| 342 | QITX | QIT-FER ET TITANE INC | | | SCAC4 |
| 343 | QIZ | QUALITY INDUSTRY | | | PWRC |
| 344 | QJ | Jet Airways, Inc. | IATA Prefix: 508, | USA | AVCODES |
| 345 | QJ | LATPASS Airlines | ICAO: LTP, Callsign: Latpass, IATA Prefix: 937, Designator QJ* and Prefix Code 937 recalled by IATA | LV | AVCODES |
| 346 | QJ | Paramount Airways | ICAO: PAT, Callsign: Paramount, Founded in October 1986. Ceased operations on 15 November 1989. | GB | AVCODES |
| 347 | QJA | Quickjet Aviation (Pty) Ltd. | Callsign: Quickjet, | NAM | AVCODES |
| 348 | QJMD | QUIROGA JIMENEZ, EDUARDO | | | SCAC4 |
| 349 | QJML | QINGDAO JET MARINE LOGISTICS CO LTD | | | SCAC4 |
| 350 | QJRT | QUEZADA, J R TRUCKING | | | SCAC4 |
| 351 | QJSW | Q JAKE SHIPPING LTD | | | SCAC4 |
| 352 | QJT | Qingdao Jiutian-Spartan International Flight Academy, Co., Ltd | Callsign: Jiu Tian, Name changed to Qingdao Jiutian International Flight Academy Co., Ltd. | PRC | AVCODES |
| 353 | QJT | Qingdao Jiutian International Flight Academy Co., Ltd. | Callsign: Jiu Tian, Name changed from Qingdao Jiutian International Flight Academy Co., Ltd. | PRC | AVCODES |
| 354 | QJTL | QUINN, J TRUCKING LLC | | | SCAC4 |
| 355 | QJTS | QJ TRANSFER & STORAGE | | | SCAC3 |
| 356 | QK | Air Canada Regional, Inc. | ICAO: ARN, Callsign: Transcan, IATA Prefix: 983, Name changed to Air Canada Jazz. ICAO Designator changed to JZZ. Name changed from Air Nova Inc. ICAO callsign changed from Nova. | CDN | AVCODES |
| 357 | QK | Air Nova, Inc. | ICAO: ARN, Callsign: Nova, IATA Prefix: 983, Merged into Air Canada Regional Inc. during 2001. Air Canada Connector | CDN | AVCODES |
| 358 | QK | Air Canada Jazz | ICAO: JZZ, Callsign: Jazz, ICAO designator changed to JZA. Name changed from Air Canada Regional Inc. ICAO designator changed from ARN. ICAO callsign changed from Transcan. | CDN | AVCODES |
| 359 | QK | Air Canada Jazz | ICAO: JZA, Callsign: Jazz, ICAO designator changed from JZZ. Name changed from Air Canada Regional Inc. ICAO designator changed from ARN. ICAO callsign changed from Transcan. | CDN | AVCODES |
| 360 | QK | Compagnie Aeromaritime d'affretement | ICAO: QKL, Callsign: Aeromar, IATA designator changed to OV | F | AVCODES |
| 361 | QK | Jazz Aviation LP | ICAO: JZA, Callsign: Jazz, Name changed from Air Canada Jazz. ICAO designator changed from JZZ. Name changed from Air Canada Regional Inc. ICAO designator changed from ARN. ICAO callsign changed from Transcan. | CDN | AVCODES |
| 362 | QKC | Aero Taxi Aviation, Inc. | Callsign: Quaker City, | USA | AVCODES |
| 363 | QKC | Aero Taxi Aviation | | | ICAO1 |
| 364 | QKCC | QUICK CAB CO | | | SCAC3 |
| 365 | QKCI | QWIK COURIERS | | | SCAC3 |
| 366 | QKCS | QUICK COURIER SERVICE | | | SCAC3 |
| 367 | QKCS | QUICK COURIER SERVICE INC | | | SCAC4 |
| 368 | QKDL | QUICK DELIVERY | | | SCAC3 |
| 369 | QKDS | QUICK DELIVERY SERVICE | | | SCAC3 |
| 370 | QKDS | QUICK DELIVERY SERVICE | | | SCAC4 |
| 371 | QKDV | QUICK DELIVERY | | | SCAC3 |
| 372 | QKDV | QUICK DELIVERY | | | SCAC4 |
| 373 | QKFI | QUICK FREIGHT INC | | | SCAC3 |
| 374 | QKFQ | QUICKSILVER FREIGHTWAYS | | | SCAC3 |
| 375 | QKFS | QUICK FREIGHT SYSTEMS | | | SCAC3 |
| 376 | QKIC | QUICK INTERNATIONAL COURIER | | | SCAC4 |
| 377 | QKJB | QUICK, JON B | | | SCAC4 |
| 378 | QKL | Aeromaritime | IATA: OV, Callsign: Aeromar, Merged into UTA | F | AVCODES |
| 379 | QKL | Compagnie Aeromaritime d'affretement | IATA: QK, Callsign: Aeromar, IATA designator changed to OV | F | AVCODES |
| 380 | QKLC | QUICK LINE CORP | | | SCAC3 |
| 381 | QKNE | QUICK N EASY MESSENGER SERVICE INC | | | SCAC3 |
| 382 | QKNE | QRC LOGISTICS (1978) LTD | | | SCAC4 |
| 383 | QKRT | QUAKER TRANSPORTATION INC | | | SCAC4 |
| 384 | QKSD | QUICK SERVICE DELIVERY AND APARTMEN | | | SCAC3 |
| 385 | QKSE | QUICK SILVER EXPRESS INC | | | SCAC3 |
| 386 | QKSI | QUICK SILVER TRANSPORT INC | | | SCAC4 |
| 387 | QKSQ | QUIK SERVICE DELIVERY | | | SCAC3 |
| 388 | QKSR | QUICKSILVER CARTAGE CO INC | | | SCAC3 |
| 389 | QKST | QUICKSILVER TRANSPORTATION INC | | | SCAC3 |
| 390 | QKSV | QUICK SILVER TRUCKING CO | | | SCAC3 |
| 391 | QKSV | QUICKSERVICE TECHNOLOGIES INC | | | SCAC4 |
| 392 | QKTF | QUIK'N TASTY FOODS INC | | | SCAC4 |
| 393 | QKTG | QUICK TRUCKING | | | SCAC3 |
| 394 | QKTK | QUICK TRUCKING | | | SCAC3 |
| 395 | QKTP | QUICK TRIP | | | SCAC4 |
| 396 | QKTR | QUICK TRUCKING INC | | | SCAC3 |
| 397 | QKWA | QUICK-WAY INC | | | SCAC3 |
| 398 | QKWA | QUICK-WAY INC | | | SCAC4 |
| 399 | QKWD | QUICKWAY DELIVERIES | | | SCAC3 |
| 400 | QKWE | QUICK WAY EXPRESS | | | SCAC3 |
