| 1 | CAS | Christman Air System | Callsign: Christman, | USA | AVCODES |
| 2 | CAS | Christman Air System | | | ICAO1 |
| 3 | CAS | CITIZEN EXPRESS LINES | | | SCAC4 |
| 4 | CASA | CASA TRUCKING | | | SCAC4 |
| 5 | CASB | CASKEY BROTHERS | | | SCAC3 |
| 6 | CASB | CR AMERICAS SHIPPING COMPANY LIMITE | | | SCAC4 |
| 7 | CASC | CASS COUNTY PUBLIC TRANSPORTATION | | | SCAC3 |
| 8 | CASD | CASS INC | | | SCAC4 |
| 9 | CASE | CALIFORNIA SIERRA EXPRESS INC | | | SCAC4 |
| 10 | CASE | | | USA | TRAFFIC |
| 11 | CASF | CASSENS TRANSPORT COMPANY | | | SCAC3 |
| 12 | CASG | CASSERINOS | | | SCAC3 |
| 13 | CASI | CASSIL FREIGHT INC | | | SCAC3 |
| 14 | CASI | CASSIL FREIGHT INC | | | SCAC4 |
| 15 | CASJ | CASSITTO BROS MOVING & STORAGE CORP | | | SCAC3 |
| 16 | CASK | CASSCO REFRIGERATED TRANSPORT | | | SCAC3 |
| 17 | CASK | C A S TRUCKING | | | SCAC4 |
| 18 | CASL | CASTLE LINES INC | | | SCAC3 |
| 19 | CASL | CASS TRUCKING INC | | | SCAC4 |
| 20 | CASN | CASWELL VAN LINES | | | SCAC3 |
| 21 | CASN | CASTANEDA MORAN, JUAN CARLOS | | | SCAC4 |
| 22 | CASO | CP Rail (CASO) | added 7/1985; eliminated 10/1987; 1/1994-7/2005 | | NAKINA |
| 23 | CASO | Consolidated Rail Corp. | added 4/1976; eliminated 4/1977; 1/1980 | | NAKINA |
| 24 | CASO | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/1976 | | NAKINA |
| 25 | CASO | Penn Central Transportation Co. (Canada Southern Ry.) | 1/1975 | | NAKINA |
| 26 | CASO | Canada Southern Ry. (New York Central System) | 10/1966 | | NAKINA |
| 27 | CASO | Canada Southern Ry. | 1/1943-7/1965 | | NAKINA |
| 28 | CASO | Canada Southern Ry. | 1/52-7/65 | | NRHS |
| 29 | CASO | Canada Southern Ry. (New York Central System) | Oct-66 | | NRHS |
| 30 | CASO | Penn Central Transportation Co. (Canada Southern Ry.) | Jan-75 | | NRHS |
| 31 | CASO | Penn Central Transportation Co., Robert W. Blanchette, Richard C. Bond and John H. McArthur, Trustees | eliminated 4/76 | | NRHS |
| 32 | CASO | Consolidated Rail Corp. | added 4/76; 1/80 | | NRHS |
| 33 | CASO | *CONSOLIDATED RAIL CORP. [PENN CENTRAL TRANSPORTATION CO.; NEW YORK CENTRAL SYSTEM, CANADIAN SOUTHERN RWY.] | | | PWRC |
| 34 | CASO | +CP RAIL [CANADA SOUTHERN RY] | | | PWRC |
| 35 | CASO | Canada Southern Railway (Canadian Pacific Railway) | | | RSRV |
| 36 | CASO | CP RAIL (CASO) | | | SCAC3 |
| 37 | CASO | CP RAIL (CASO) | | | SCAC4 |
| 38 | CASO | Canada Southern Ry. | | CDN | TRAFFIC |
| 39 | CASP | CASTO TRAVEL CORP | | | SCAC3 |
| 40 | CASP | CHAMPS AUTO SPORT TRANSPORT | | | SCAC4 |
| 41 | CASQ | CASE CARTAGE INC | | | SCAC3 |
| 42 | CASR | CASCADE RECREATIONAL RAILROAD | | | PWRC |
| 43 | CASR | CASCO SERVICES INC | | | SCAC3 |
| 44 | CASS | CASS SCENIC RAILROAD (STATE OF WEST VIRGINIA) | | | PWRC |
| 45 | CASS | CASSIDYS TRANSFER & STORAGE LIMITED | | | SCAC4 |
| 46 | CAST | CAST NORTH AMERICA INC. | | | SCAC3 |
| 47 | CAST | CAUSTIC SODA TRANSPORTATION COMPANY | | | SCAC4 |
| 48 | CASU | HAPAG LLOYD A.G | | D | BIC |
| 49 | CASU | CAST NORTH AMERICA | | | SCAC3 |
| 50 | CASU | CP SHIPS | | | SCAC4 |
| 51 | CASV | CASTLE TRUCKING CO | | | SCAC3 |
| 52 | CASW | CARRIER TRANSPORT SERVICE OF CALIFO | | | SCAC3 |
| 53 | CASW | C A S TRANSPORTATION INC | | | SCAC4 |
| 54 | CASZ | CALIFORNIA STEEL, INC. | | | PWRC |