| 1 | CLA | Color Air | Callsign: Pennant, Commenced operations on 01 August 1998. Ceased operations on 27 September 1999. Commenced operations on 01 August 1998. | N | AVCODES |
| 2 | CLA | Colombia | IATA: KW, Callsign: Columbia, | I | AVCODES |
| 3 | CLA | Comlux Aviation AG | Callsign: Comlux, | CH | AVCODES |
| 4 | CLA | Comlux Aviation | | | ICAO1 |
| 5 | CLA | Chełmskie Linie Autobusowe Spółka z o.o. | City: Chelm | PL | TRAFFIC |
| 6 | CLAA | C-LA TRUCKING INC | | | SCAC4 |
| 7 | CLAB | CLAUDES INC | | | SCAC3 |
| 8 | CLAC | CLANCY-CULLEN STORAGE CO, INC | | | SCAC3 |
| 9 | CLAD | CLANCYS DELIVERY SERVICE | | | SCAC3 |
| 10 | CLAE | CLAUSEN TRANSFER AND STORAGE INC | | | SCAC3 |
| 11 | CLAE | CLARK, W A TRUCKING INC | | | SCAC4 |
| 12 | CLAF | COLONIAL AIR EXPRESS | | | SCAC3 |
| 13 | CLAG | CLANCY, GEORGE M CARTING CO INC | | | SCAC3 |
| 14 | CLAG | CLELAND SITE PREP INC | | | SCAC4 |
| 15 | CLAH | CLAUSEN, J C | | | SCAC3 |
| 16 | CLAI | CLARK, ALLEN INC | | | SCAC3 |
| 17 | CLAI | CALLAHAN BUS LINES INC | | | SCAC4 |
| 18 | CLAJ | CLA INC | | | SCAC4 |
| 19 | CLAK | CAL-ARK INTERNATIONAL INC | | | SCAC4 |
| 20 | CLAM | CROWLEY LATIN AMERICA SERVICES LLC | | | SCAC4 |
| 21 | CLAN | CLANCY CARTING & STORAGE CO INC | | | SCAC3 |
| 22 | CLAO | CLAREDEN-BRETON TRUCK | | | SCAC3 |
| 23 | CLAO | CASELLA TRANSPORTATION INC | | | SCAC4 |
| 24 | CLAP | CRESCENT SHIPPERS OF LA INC | | | SCAC4 |
| 25 | CLAR | CLARION RIVER RWY. | | | PWRC |
| 26 | CLAR | CLARKSON BROS MACHINERY HAULERS, IN | | | SCAC3 |
| 27 | CLAR | CLARKSON BROS MACHINERY HAULERS, IN | | | SCAC4 |
| 28 | CLARI | CLARIANT SPECIALTY FINE CHEMICALS (France) S.A.S. | | FR | VKM |
| 29 | CLAS | CLINTON ALUMINUM & STAINLESS STEEL | | | SCAC4 |
| 30 | CLASB | Classic Bus Hire | | GB | TRAFFIC |
| 31 | CLASC | Classic Charter (Ludwig & Son) | | CDN | TRAFFIC |
| 32 | CLAT | CLATTERBUCK HORSE TRANSPORTATION | | | SCAC3 |
| 33 | CLAT | CLARY TRUCKING INC | | | SCAC4 |
| 34 | CLAT | Classic Tours | | US-NJ | TRAFFIC |
| 35 | CLAU | CLASQUIN SA | | F | BIC |
| 36 | CLAU | CONTI LINES N V | | | SCAC4 |
| 37 | CLAV | CLAVIERS BAROQUES | | | SCAC4 |
| 38 | CLAX | Guardian Leasing, Inc. | 7/2005 (not listed) | | NAKINA |
| 39 | CLAX | Clayton Oil & Refining Co. | 7/1923 | | NAKINA |
| 40 | CLAX | *CLAYTON OIL & REFINING CO. | | | PWRC |
| 41 | CLAX | +GUARDIAN LEASING, INC. | | | PWRC |
| 42 | CLAX | GUARDIAN LEASING INC | | | SCAC4 |
| 43 | CLAY | CLAY CENTER FREIGHT SERVICE | | | SCAC3 |
| 44 | CLAY | CLAYTON INDUSTRIES | | | SCAC4 |
