| 1 | CP | CP Air | ICAO: CPC, Callsign: Empress, Bought by Pacific Western and merged to form Canadian Airlines International | CDN | AVCODES |
| 2 | CP | Capitol Airways | ICAO: CAL, Callsign: Capitol, Ceased operations | GB | AVCODES |
| 3 | CP | Canadian Airlines International Limited | ICAO: CDN, Callsign: Canadian, Merged into Air Canada. Formerly CP Air | CDN | AVCODES |
| 4 | CP | Canadian Pacific Airlines Ltd. | ICAO: CPC, Callsign: Empress, Name changed to Canadian Airlines International Ltd. Name changed from CP Air | CDN | AVCODES |
| 5 | CP | Compass Airlines LLC | ICAO: CPZ, Callsign: Compass Rose, IATA Prefix: 003, ICAO Callsign changed to Compass. | USA | AVCODES |
| 6 | CP | Compass Airlines LLC | ICAO: CPZ, Callsign: Compass, IATA Prefix: 003, Ceased operation on 05 April 2020. ICAO Callsign changed from Compass Rose. Wholly-owned subsidiary of Trans States Holdings, Inc. | USA | AVCODES |
| 7 | CP | Aliscargo Airlines S.p.A. | ICAO: LSI, Callsign: Alis, IATA Prefix: 233, | I | AVCODES |
| 8 | CP | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 9 | CP | CP Rail System | eliminated 1/1997 | | NAKINA |
| 10 | CP | Canadian Pacific Ry. | 8/1920-10/1966 | | NAKINA |
| 11 | CP | CP Rail | 1/1975-1/1994 | | NAKINA |
| 12 | CP | Canadian Pacific Ry. | 7/23-10/66 | | NRHS |
| 13 | CP | CP Rail | 1/75-1/94 | | NRHS |
| 14 | CP | CP Rail System | eliminated 1/97 | | NRHS |
| 15 | CP | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | | NRHS |
| 16 | CP | CP RAIL [CANADIAN PACIFIC RWY.] | | | PWRC |
| 17 | CP | Canadian Pacific Railway | | | RSRV |
| 18 | CP | CP RAIL SYSTEM | | | SCAC4 |
| 19 | CP | Comboios de Portugal | | P | TRAFFIC |
| 20 | CP | Caminhos de Ferro Portugeses, E.P. | | PT | VKM |
| 21 | CPA | Cathay Pacific Airways Ltd. | IATA: CX, Callsign: Cathay, IATA Prefix: 160, ICAO designator changed from CPX | HK | AVCODES |
| 22 | CPA | Capital Air Service, Inc. | Callsign: Capair, | USA | AVCODES |
| 23 | CPA | Cathay Pacific | IATA: CX | | ICAO1 |
| 24 | CPA | Coudersport & Port Allegany | 1/1975-1/1980 | | NAKINA |
| 25 | CPA | Cumberland & Pennsylvania R.R. | 4/1938-7/1954 | | NAKINA |
| 26 | CPA | Cumberland & Pennsylvania R.R. | 4/38-1/52 | | NRHS |
| 27 | CPA | Coudersport & Port Allegany | 1/75-1/80 | | NRHS |
| 28 | CPA | *CSX TRANSPORTATION [WESTERN MARYLAND; CUMBERLAND & PENNSYLVANIA RR] | | | PWRC |
| 29 | CPA | *COUDERSPORT & PORT ALLEGHENY RAILROAD | | | PWRC |
| 30 | CPA | Cathay Pacific | | HK | TRAFFIC |
| 31 | CPAA | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 32 | CPAA | CP Rail System | eliminated 1/1997 | | NAKINA |
| 33 | CPAA | CP Rail | 1/1975-1/1994 | | NAKINA |
| 34 | CPAA | CP Rail | 1/75-1/94 | | NRHS |
| 35 | CPAA | CP Rail System | eliminated 1/97 | | NRHS |
| 36 | CPAA | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | | NRHS |
| 37 | CPAA | CP RAIL [CANADIAN PACIFIC RWY.] | | | PWRC |
| 38 | CPAA | Canadian Pacific Railway | | | RSRV |
| 39 | CPAC | COMPAC TRANSPORTATION | | | SCAC3 |
| 40 | CPAC | CAMPBELL, A C TRANSPORT INC | | | SCAC4 |
| 41 | CPAD | CAPE ANN TRANSPORT INC | | | SCAC3 |
| 42 | CPAD | C P CARRIER INC | | | SCAC4 |
| 43 | CPAE | CORNPATCH EXPRESS INC | | | SCAC3 |
| 44 | CPAF | CPS INDUSTRIES | | | SCAC4 |
| 45 | CPAG | CHAMPAIGN TRUCKS INC | | | SCAC3 |
| 46 | CPAH | CORPORATE AIR EXPRESS | | | SCAC3 |
| 47 | CPAI | COTPAC | | | SCAC3 |
| 48 | CPAK | C-BAR-J CORP | | | SCAC4 |
| 49 | CPAM | COMPASS MARINE SERVICE | | | SCAC3 |
| 50 | CPAO | CONTINENTAL TRANSPORTATION & DISTRI | | | SCAC4 |
| 51 | CPAP | COMPAC TRANSPORTATION | | | SCAC3 |
| 52 | CPAP | COMPAC TRANSPORTATION | | | SCAC4 |
| 53 | CPAQ | CAPONE, ALBERT TRUCKING INC | | | SCAC3 |
| 54 | CPAR | CHAMPALAS TRUCKING | | | SCAC4 |
| 55 | CPAS | COPP & ASSOCIATES INC | | | SCAC4 |
| 56 | CPAT | COMPLETE AUTO TRANSIT INCC | | | SCAC3 |
| 57 | CPAT | CONSULTANT P A T | | | SCAC4 |
| 58 | CPAU | COMBIPASS SAS | | F | BIC |
| 59 | CPAU | COMBIPASS SAS | | | SCAC4 |
| 60 | CPAV | COUPE & COMPANY | | | SCAC4 |
| 61 | CPAX | CITGO Petroleum Corp. | added 7/1993; 1/1994-7/2005; eliminated 4/2008 | | NAKINA |
| 62 | CPAX | Compania Mexicana de Petroleo ""El Aguila"", S.A. | 7/1937-4/1938 | | NAKINA |
| 63 | CPAX | Compania Mexicana de Petroleo "El Agila", S.A. | Apr-38 | | NRHS |
| 64 | CPAX | CITGO Petroleum Corp. | added 7/93; 1/94-7/2000 | | NRHS |
| 65 | CPAX | *COMPANIA MEXICANA DE PETROLEO "EL AGUILA", S. A. | | | PWRC |
| 66 | CPAX | *CITGO PETROLEUM CORPORATION | | | PWRC |
| 67 | CPAX | +NUSTAR MARKETING, LLC | | | PWRC |
| 68 | CPAX | CITGO Petroleum Corporation | | | RSRV |
| 69 | CPAX | CITGO PETROLEUM CORP. | | | SCAC4 |
| 70 | CPAY | CAL PAC TRANSPORT INCORPORATED | | | SCAC3 |
| 71 | CPAZ | COPLANT | | | PWRC |
| 72 | CPB | Corpac Canada Ltd. | Callsign: Penta, Ceased Operations on 18 June 2009. | CDN | AVCODES |
| 73 | CPB | Corpac Canada | | | ICAO1 |
| 74 | CPB | Companhia Paulista de Estradas de Ferro / S?o Paulo Railway Company | Real: CP | BR | TRAFFIC |
| 75 | CPBA | CAPABLE TRANSPORT INC | | | SCAC4 |
| 76 | CPBB | CAPITOL BUS CO | | | SCAC3 |
| 77 | CPBB | CARDINAL SHIPPING LLC | | | SCAC4 |
| 78 | CPBC | CAMPBELL OIL COMPANY | | | SCAC4 |
| 79 | CPBE | CAMPBELL FREIGHT INC | | | SCAC4 |
| 80 | CPBG | CORP TRANSPORTATION BROKERAGE | | | SCAC3 |
| 81 | CPBG | CONE TRANSPORTATION | | | SCAC4 |
| 82 | CPBH | CAMPER BROTHERS TRUCKING | | | SCAC3 |
| 83 | CPBI | CRANE PLUMBING INC | | | SCAC3 |
| 84 | CPBJ | CHAMPION BUS CO INC | | | SCAC3 |
| 85 | CPBJ | CAMPBELL, GERRY TRUCKING | | | SCAC4 |
| 86 | CPBK | CP BULK SHIPS | | | SCAC3 |
| 87 | CPBN | CORSO, P BANANA TRANSPORT | | | SCAC3 |
| 88 | CPBO | CAMPBELL BROS MOVING & STORAGE CO | | | SCAC3 |
| 89 | CPBP | COLOPINTO BUS CO | | | SCAC3 |
| 90 | CPBQ | CAMPBELL TRANSPORTATION | | | SCAC3 |
| 91 | CPBR | CRUMP BROS TRUCKING INC | | | SCAC3 |
| 92 | CPBS | CAMPBELL, S B INC | | | SCAC3 |
| 93 | CPBS | CAMERO TRANSPORT INC | | | SCAC4 |
| 94 | CPBT | CAMPBELL TRUCKING | | | SCAC3 |
| 95 | CPBU | CANONS PARK EQUIPMENT CO LTD | | HK | BIC |
| 96 | CPBU | SOO LINE RAILROAD | | | PWRC |
| 97 | CPBU | Soo Line (Canadian Pacific Railway) | | | RSRV |
| 98 | CPBU | CP RAIL INTERMODAL FREIGHT SYSTEM | | | SCAC3 |
| 99 | CPBU | CP RAIL INTERMODAL FREIGHT SYSTEM | | | SCAC4 |
| 100 | CPBW | CANADIAN PACIFIC (BERMUDA) LIMITED | | | SCAC3 |