| 1 | CAP | Capitol Airlines, Inc. | IATA: CL, Callsign: Capitol, Desigantor CL recalled by IATA | USA | AVCODES |
| 2 | CAP | U.S. Air Force Auxiliary/Civil Air Patrol | Callsign: Cap, | USA | AVCODES |
| 3 | CAPB | Capital Bus | City: Taipei | RC | TRAFFIC |
| 4 | CAPC | Capital Coaches | | GB | TRAFFIC |
| 5 | CAPD | CAMPUS DIVISION OF PEYLIM | | | SCAC3 |
| 6 | CAPE | CAPITOL STORAGE CORPORATION | | | SCAC3 |
| 7 | CAPG | CAPITOL TRANSPORTATION GROUP INC | | | SCAC4 |
| 8 | CAPI | CAROLINA PARCEL INC | | | SCAC4 |
| 9 | CAPJ | CAPITAL EXPRESS INC | | | SCAC3 |
| 10 | CAPJ | CARDAN TRANSPORT | | | SCAC4 |
| 11 | CAPK | CAMPBELL, VERN TRANSPORT INC | | | SCAC3 |
| 12 | CAPL | CAPITAL EXPRESS INC | | | SCAC4 |
| 13 | CAPM | CAPPS TRUCKING | | | SCAC3 |
| 14 | CAPO | CAPP HOMES DIVISION (EVANS PRODUCTS | | | SCAC3 |
| 15 | CAPP | CAN AM PRECAST PRODUCTS LTD | | | SCAC4 |
| 16 | CAPQ | CAPPOZZI TRUCK LINES | | | SCAC3 |
| 17 | CAPR | Carolina Piedmont Division, South Carolina Central R.R. Co., Inc. | | USA | TRAFFIC |
| 18 | CAPS | CAPLES TRUCKING | | | SCAC3 |
| 19 | CAPS | CAPS INC | | | SCAC4 |
| 20 | CAPT | CAPONEY TIRE TRUCKING INC | | | SCAC3 |
| 21 | CAPT | CapTrain | | EU | TRAFFIC |
| 22 | CAPTRAM | Cape Tramways | City: Cape Town | ZA | TRAFFIC |
| 23 | CAPU | CAPE CONTAINER LINE (UK) LTD | | GB | BIC |
| 24 | CAPU | CAPE CONTAINERS LEASING LTD | | | SCAC3 |
| 25 | CAPU | CONS A R P SOCIETA | | | SCAC4 |
| 26 | CAPX | TransAlta Utilities Corp. | added 10/1981; 1/1994-7/2000; eliminated 4/2002; 7/2005 (not listed) | | NAKINA |
| 27 | CAPX | Clay Arthur Pierce (Pierce Oil Corp.) | 8/1920 | | NAKINA |
| 28 | CAPX | The Capital City Products Co. | 1/1941-4/1961; eliminated 7/1965 | | NAKINA |
| 29 | CAPX | The Capital City Products Co. | 1/52-4/61; eliminated 7/65 | | NRHS |
| 30 | CAPX | TransAlta Utilities Corp. | added 10/81; 1/94-7/2000 | | NRHS |
| 31 | CAPX | *CLAY ARTHUR PIERCE (PIERCE OIL CORP.) | | | PWRC |
| 32 | CAPX | *CAPITAL CITY PRODUCTS CO. | | | PWRC |
| 33 | CAPX | +TRANSALTA UTILITIES CORPORATION | | | PWRC |
| 34 | CAPX | Capital City Products (TransAlta Utilities) | | | RSRV |
| 35 | CAPX | CANADA PACKERS LTD | | | SCAC3 |
| 36 | CAPX | TRANSALTA UTILITIES CORPORATION | | | SCAC4 |
| 37 | CAPZ | CAL PORTLAND CEMENT | | | PWRC |
| 38 | CAPZ | CAPES SHIPPING AGENCIES, INC | | | SCAC3 |