| 1 | PQ | PTL Luftfahrtunternehmen GmbH. | ICAO: KST, Callsign: King Star, Designator PQ recalled by IATA | D | AVCODES |
| 2 | PQ | Air Transafrik Limited | ICAO: TRF, Callsign: Transafrik, Designator PQ recalled by IATA | GH | AVCODES |
| 3 | PQ | Tashkent Aircraft Production Corporation | ICAO: CTP, Callsign: Cortas, IATA designator changed to 4C* | UZ | AVCODES |
| 4 | PQ | Bogazici Hava Tasimacilik A.S. | ICAO: BHT, Callsign: Basfir, | TR | AVCODES |
| 5 | PQ | Tropical International Airways Ltd. | ICAO: TKX, Callsign: Tropexpress, Designator PQ recalled by IATA | SKN | AVCODES |
| 6 | PQ | Panafrican Airways | ICAO: PNF, Callsign: Panways, | CI | AVCODES |
| 7 | PQ | Puerto Rico International Airlines, Inc. | Callsign: Prinair, | PRI | AVCODES |
| 8 | PQ | Aerosur Paraguay S.A. | ICAO: AES, Callsign: Aeroparaguay, IATA Prefix: 682, Ceased operations on 01 July 2012. Name changed from Aero Regional Paraguaya S.A. | PY | AVCODES |
| 9 | PQ | AirAsia, Inc. Philippines | ICAO: APG, Callsign: Cool Red, IATA Prefix: 062, Merged with Philippines AirAsia Inc. (Z2/EZD) in January 2016. | RP | AVCODES |
| 10 | PQ | SkyUp Airlines | ICAO: SQP, Callsign: Skyup, IATA Prefix: 010, ICAO code changed from KUP w.e.f. 17 August 2018. | UA | AVCODES |
| 11 | PQA | Pacific Coast Airlines | Callsign: Sage Brush, | USA | AVCODES |
| 12 | PQA | Pacific Coast Airlines | IATA: ID, Callsign: Sage Brush, | USA | AVCODES |
| 13 | PQA | Pacific Coast Airlines | | | ICAO1 |
| 14 | PQAR | PAQUETTE, A R & CO | | | SCAC3 |
| 15 | PQAR | PAQUETTE, A R & CO | | | SCAC4 |
| 16 | PQBK | PRO QUO BOOKS | | | SCAC4 |
| 17 | PQC | Chieftain Airways plc | Callsign: Chieftain, | GB | AVCODES |
| 18 | PQCC | PETROLEUM CARRIERS LLC | | | SCAC4 |
| 19 | PQCG | PETROEAST COMPRESSED GASSES LLC | | | SCAC4 |
| 20 | PQCL | PRINCIPAL CONTAINER LINE | | | SCAC3 |
| 21 | PQCX | The PQ Corp. | added 4/1980; 1/1994; eliminated 1/1995; 7/2000-7/2005 (not listed) | | NAKINA |
| 22 | PQCX | PQ Corp. | added 4/1978; 1/1980; eliminated 4/1980 | | NAKINA |
| 23 | PQCX | Philadelphia Quartz Co. | added 1/1971; 1/1975; eliminated 4/1978 | | NAKINA |
| 24 | PQCX | Philadelphia Quartz Co. of California | 8/1920-7/1923 | | NAKINA |
| 25 | PQCX | Philadelphia Quartz Co. of California, Ltd. | 7/1930-4/1970; eliminated 1/1971 | | NAKINA |
| 26 | PQCX | Philadelphia Quartz Co. of California, Ltd. | 4/38-4/70; eliminated 1/71 | | NRHS |
| 27 | PQCX | Philadelphia Quartz Co. | added 1/71; 1/75; eliminated 4/78 | | NRHS |
| 28 | PQCX | PQ Corp. | added 4/78; 1/80; eliminated 4/80; 7/2000 | | NRHS |
| 29 | PQCX | The PQ Corp. | added 4/80; 1/94; eliminated 1/95; 7/2000 | | NRHS |
| 30 | PQCX | (PQX) PQ CORPORATION [PHILADELPHIA QUARTZ CO.] | | | PWRC |
| 31 | PQCX | PQ Corporation | | | RSRV |
| 32 | PQCX | PHILADELPHIA QUARTZ COMPANY OF CALI | | | SCAC3 |
| 33 | PQCX | PQ CORPORATION | | | SCAC4 |
| 34 | PQEL | PETROFIL TANK LINES | | | SCAC4 |
| 35 | PQEN | PENA TRUCKING SERVICES INC | | | SCAC4 |
| 36 | PQFC | PAQUET & FAUCHER | | | SCAC4 |
| 37 | PQFD | PENQUITO FOODS | | | SCAC4 |
| 38 | PQIS | PRESQUE ISLE TRUCKING CO INC | | | SCAC3 |
| 39 | PQIU | UNITAS CONTAINERS LIMITED | | BM | BIC |
| 40 | PQKA | PETKA SHIPPING COMPANY LIMITED | | | SCAC3 |
| 41 | PQKA | PRESSLINE EQUIPMENT | | | SCAC4 |
| 42 | PQKL | PATROKLOS SHIPPING COMPANY LIMITED | | | SCAC3 |
| 43 | PQKR | PARKER, MIKE TRUCKING CO | | | SCAC4 |
| 44 | PQLI | PARLI TRUCKING | | | SCAC3 |
| 45 | PQLV | PLITVICE SHIPPING COMPANY LIMITED | | | SCAC3 |
| 46 | PQMR | PREMIER TRANSPORTATION LLC | | | SCAC4 |
| 47 | PQNQ | PIQUNIQ MANAGEMENT CORPORATION | | | SCAC3 |
| 48 | PQOL | PHILI-ORIENT LINES LTD | | | SCAC3 |
| 49 | PQON | PRO OIL INC | | | SCAC4 |
| 50 | PQOS | PARENTES OIL SERVICE INC | | | SCAC4 |
| 51 | PQOT | PRICE, O L TRUCKING INC | | | SCAC4 |
| 52 | PQRE | PRECISION GROUP | | | SCAC4 |
| 53 | PQRL | PEQUIGNOT, R & L TRUCKING | | | SCAC3 |
| 54 | PQRQ | P R S TRANSIT | | | SCAC4 |
| 55 | PQRR | PORRONE TRANSPORT | | | SCAC4 |
| 56 | PQRY | PROACTIVE RECYCLING INC | | | SCAC4 |
| 57 | PQSC | PELJESAC SHIPPING COMPANY LIMITED | | | SCAC3 |
| 58 | PQSH | PROSE SHIPPING LIMITED | | | SCAC3 |
| 59 | PQSI | PRESTRESSED SYSTEMS INC | | | SCAC4 |
| 60 | PQSS | PRO-SPEED SHIPPING INC MONTEREY PAR | | | SCAC3 |
| 61 | PQTC | PTC | | | SCAC4 |
| 62 | PQTE | PAQUET ET FILS LTEE | | | SCAC4 |
| 63 | PQTI | PDQ TRANSPORT INC | | | SCAC3 |
| 64 | PQTK | PARMER TRUCKING CO LLC | | | SCAC4 |
| 65 | PQTR | PRO TRANSPORT INC | | | SCAC4 |
| 66 | PQTS | PORT TRANSPORT INC | | | SCAC4 |
| 67 | PQUN | PETROQUIN TRANSPORT INC | | | SCAC4 |
| 68 | PQX | The PQ Corp | added 4/1980; 1/1994-7/2005 | | NAKINA |
| 69 | PQX | PQ Corp | added 4/1978; 1/1980; eliminated 4/1980 | | NAKINA |
| 70 | PQX | Philadelphia Quartz Co. | 8/1920; 7/1930-1/1975; eliminated 4/1978 | | NAKINA |
| 71 | PQX | Philadelphia Quartz Co. | 4/38-1/75; eliminated 4/78 | | NRHS |
| 72 | PQX | PQ Corp | added 4/78; 1/80; eliminated 4/80 | | NRHS |
| 73 | PQX | The PQ Corp | added 4/80; 1/94-7/2000 | | NRHS |
| 74 | PQX | PQ CORPORATION [PHILADELPHIA QUARTZ CO.] | | | PWRC |
| 75 | PQX | PQ Corporation | | | RSRV |
| 76 | PQX | PQ CORPORATION | | | SCAC4 |
