| 1 | CPA | Cathay Pacific Airways Ltd. | IATA: CX, Callsign: Cathay, IATA Prefix: 160, ICAO designator changed from CPX | HK | AVCODES |
| 2 | CPA | Capital Air Service, Inc. | Callsign: Capair, | USA | AVCODES |
| 3 | CPA | Cathay Pacific | IATA: CX | | ICAO1 |
| 4 | CPA | Coudersport & Port Allegany | 1/1975-1/1980 | | NAKINA |
| 5 | CPA | Cumberland & Pennsylvania R.R. | 4/1938-7/1954 | | NAKINA |
| 6 | CPA | Cumberland & Pennsylvania R.R. | 4/38-1/52 | | NRHS |
| 7 | CPA | Coudersport & Port Allegany | 1/75-1/80 | | NRHS |
| 8 | CPA | *CSX TRANSPORTATION [WESTERN MARYLAND; CUMBERLAND & PENNSYLVANIA RR] | | | PWRC |
| 9 | CPA | *COUDERSPORT & PORT ALLEGHENY RAILROAD | | | PWRC |
| 10 | CPA | Cathay Pacific | | HK | TRAFFIC |
| 11 | CPAA | Canadian Pacific Ry. Co. | added 1/1997; 7/2000-7/2005 | | NAKINA |
| 12 | CPAA | CP Rail System | eliminated 1/1997 | | NAKINA |
| 13 | CPAA | CP Rail | 1/1975-1/1994 | | NAKINA |
| 14 | CPAA | CP Rail | 1/75-1/94 | | NRHS |
| 15 | CPAA | CP Rail System | eliminated 1/97 | | NRHS |
| 16 | CPAA | Canadian Pacific Ry. Co. | added 1/97; 7/2000 | | NRHS |
| 17 | CPAA | CP RAIL [CANADIAN PACIFIC RWY.] | | | PWRC |
| 18 | CPAA | Canadian Pacific Railway | | | RSRV |
| 19 | CPAC | COMPAC TRANSPORTATION | | | SCAC3 |
| 20 | CPAC | CAMPBELL, A C TRANSPORT INC | | | SCAC4 |
| 21 | CPAD | CAPE ANN TRANSPORT INC | | | SCAC3 |
| 22 | CPAD | C P CARRIER INC | | | SCAC4 |
| 23 | CPAE | CORNPATCH EXPRESS INC | | | SCAC3 |
| 24 | CPAF | CPS INDUSTRIES | | | SCAC4 |
| 25 | CPAG | CHAMPAIGN TRUCKS INC | | | SCAC3 |
| 26 | CPAH | CORPORATE AIR EXPRESS | | | SCAC3 |
| 27 | CPAI | COTPAC | | | SCAC3 |
| 28 | CPAK | C-BAR-J CORP | | | SCAC4 |
| 29 | CPAM | COMPASS MARINE SERVICE | | | SCAC3 |
| 30 | CPAO | CONTINENTAL TRANSPORTATION & DISTRI | | | SCAC4 |
| 31 | CPAP | COMPAC TRANSPORTATION | | | SCAC3 |
| 32 | CPAP | COMPAC TRANSPORTATION | | | SCAC4 |
| 33 | CPAQ | CAPONE, ALBERT TRUCKING INC | | | SCAC3 |
| 34 | CPAR | CHAMPALAS TRUCKING | | | SCAC4 |
| 35 | CPAS | COPP & ASSOCIATES INC | | | SCAC4 |
| 36 | CPAT | COMPLETE AUTO TRANSIT INCC | | | SCAC3 |
| 37 | CPAT | CONSULTANT P A T | | | SCAC4 |
| 38 | CPAU | COMBIPASS SAS | | F | BIC |
| 39 | CPAU | COMBIPASS SAS | | | SCAC4 |
| 40 | CPAV | COUPE & COMPANY | | | SCAC4 |
| 41 | CPAX | CITGO Petroleum Corp. | added 7/1993; 1/1994-7/2005; eliminated 4/2008 | | NAKINA |
| 42 | CPAX | Compania Mexicana de Petroleo ""El Aguila"", S.A. | 7/1937-4/1938 | | NAKINA |
| 43 | CPAX | Compania Mexicana de Petroleo "El Agila", S.A. | Apr-38 | | NRHS |
| 44 | CPAX | CITGO Petroleum Corp. | added 7/93; 1/94-7/2000 | | NRHS |
| 45 | CPAX | *COMPANIA MEXICANA DE PETROLEO "EL AGUILA", S. A. | | | PWRC |
| 46 | CPAX | *CITGO PETROLEUM CORPORATION | | | PWRC |
| 47 | CPAX | +NUSTAR MARKETING, LLC | | | PWRC |
| 48 | CPAX | CITGO Petroleum Corporation | | | RSRV |
| 49 | CPAX | CITGO PETROLEUM CORP. | | | SCAC4 |
| 50 | CPAY | CAL PAC TRANSPORT INCORPORATED | | | SCAC3 |
| 51 | CPAZ | COPLANT | | | PWRC |
