| 1 | CL | Lufthansa CityLine | ICAO: CLH, Callsign: Hansaline, IATA Prefix: 683, Name changed from Lufthansa Cityline GmbH | D | AVCODES |
| 2 | CL | Lufthansa CityLine GmbH | ICAO: CLH, Callsign: Hansaline, IATA Prefix: 683, Name changed to Lufthansa Cityline | D | AVCODES |
| 3 | CL | Capitol International Airways | Callsign: Capitol, | USA | AVCODES |
| 4 | CL | Capitol Airlines, Inc. | ICAO: CAP, Callsign: Capitol, Desigantor CL recalled by IATA | USA | AVCODES |
| 5 | CL | Cargolink AS | | NO | VKM |
| 6 | 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 |
| 7 | CLA | Colombia | IATA: KW, Callsign: Columbia, | I | AVCODES |
| 8 | CLA | Comlux Aviation AG | Callsign: Comlux, | CH | AVCODES |
| 9 | CLA | Comlux Aviation | | | ICAO1 |
| 10 | CLA | Chełmskie Linie Autobusowe Spółka z o.o. | City: Chelm | PL | TRAFFIC |
| 11 | CLAA | C-LA TRUCKING INC | | | SCAC4 |
| 12 | CLAB | CLAUDES INC | | | SCAC3 |
| 13 | CLAC | CLANCY-CULLEN STORAGE CO, INC | | | SCAC3 |
| 14 | CLAD | CLANCYS DELIVERY SERVICE | | | SCAC3 |
| 15 | CLAE | CLAUSEN TRANSFER AND STORAGE INC | | | SCAC3 |
| 16 | CLAE | CLARK, W A TRUCKING INC | | | SCAC4 |
| 17 | CLAF | COLONIAL AIR EXPRESS | | | SCAC3 |
| 18 | CLAG | CLANCY, GEORGE M CARTING CO INC | | | SCAC3 |
| 19 | CLAG | CLELAND SITE PREP INC | | | SCAC4 |
| 20 | CLAH | CLAUSEN, J C | | | SCAC3 |
| 21 | CLAI | CLARK, ALLEN INC | | | SCAC3 |
| 22 | CLAI | CALLAHAN BUS LINES INC | | | SCAC4 |
| 23 | CLAJ | CLA INC | | | SCAC4 |
| 24 | CLAK | CAL-ARK INTERNATIONAL INC | | | SCAC4 |
| 25 | CLAM | CROWLEY LATIN AMERICA SERVICES LLC | | | SCAC4 |
| 26 | CLAN | CLANCY CARTING & STORAGE CO INC | | | SCAC3 |
| 27 | CLAO | CLAREDEN-BRETON TRUCK | | | SCAC3 |
| 28 | CLAO | CASELLA TRANSPORTATION INC | | | SCAC4 |
| 29 | CLAP | CRESCENT SHIPPERS OF LA INC | | | SCAC4 |
| 30 | CLAR | CLARION RIVER RWY. | | | PWRC |
| 31 | CLAR | CLARKSON BROS MACHINERY HAULERS, IN | | | SCAC3 |
| 32 | CLAR | CLARKSON BROS MACHINERY HAULERS, IN | | | SCAC4 |
| 33 | CLARI | CLARIANT SPECIALTY FINE CHEMICALS (France) S.A.S. | | FR | VKM |
| 34 | CLAS | CLINTON ALUMINUM & STAINLESS STEEL | | | SCAC4 |
| 35 | CLASB | Classic Bus Hire | | GB | TRAFFIC |
| 36 | CLASC | Classic Charter (Ludwig & Son) | | CDN | TRAFFIC |
| 37 | CLAT | CLATTERBUCK HORSE TRANSPORTATION | | | SCAC3 |
| 38 | CLAT | CLARY TRUCKING INC | | | SCAC4 |
| 39 | CLAT | Classic Tours | | US-NJ | TRAFFIC |
| 40 | CLAU | CLASQUIN SA | | F | BIC |
| 41 | CLAU | CONTI LINES N V | | | SCAC4 |
| 42 | CLAV | CLAVIERS BAROQUES | | | SCAC4 |
| 43 | CLAX | Guardian Leasing, Inc. | 7/2005 (not listed) | | NAKINA |
| 44 | CLAX | Clayton Oil & Refining Co. | 7/1923 | | NAKINA |
| 45 | CLAX | *CLAYTON OIL & REFINING CO. | | | PWRC |
| 46 | CLAX | +GUARDIAN LEASING, INC. | | | PWRC |
| 47 | CLAX | GUARDIAN LEASING INC | | | SCAC4 |
| 48 | CLAY | CLAY CENTER FREIGHT SERVICE | | | SCAC3 |
| 49 | CLAY | CLAYTON INDUSTRIES | | | SCAC4 |
| 50 | CLB | CAA Calibration Flight | Callsign: Calibrator, Name changed to Flight Precision Limited | GB | AVCODES |
| 51 | CLB | Flight Precision Limited | Callsign: Calibrator, Name changed to Cobham Flight Inspection Ltd. Formerly CAA Calibration Flight. ICAO callsign changed from Calibration | GB | AVCODES |
| 52 | CLB | Cobham Flight Inspection Limited | Callsign: Calibrator, Name changed from Flight Precision Limited. Formerly CAA Calibration Flight | GB | AVCODES |
| 53 | CLB | Flight Precision Limited | | | ICAO1 |
| 54 | CLB | Chiemgauer Lokalbahn eV | Olbing | D | privat-bahn.de |
| 55 | CLB | Chiemgauer Lokalbahn Betriebsgesellschaft mbH & Co KG | | DE | VKM |
| 56 | CLBA | COLUMBIA TRUCKING | | | SCAC3 |
| 57 | CLBB | CARROLL, BOBBY | | | SCAC3 |
| 58 | CLBC | COLUMBUS CHARTER COACH INC | | | SCAC3 |
| 59 | CLBC | COLUMBUS CHARTER COACH INC | | | SCAC4 |
| 60 | CLBD | COLBY DIRECT DELIVERY | | | SCAC4 |
| 61 | CLBE | CULBERSON TRANSPORT INC | | | SCAC4 |
| 62 | CLBF | COLUMBIA FOODS INC | | | SCAC3 |
| 63 | CLBG | CONSTRUCTORA DEL NORESTE SA | | | SCAC4 |
| 64 | CLBH | CARLSON BROTHERS | | | SCAC3 |
| 65 | CLBH | COLUMBIA EQUIPMENT SALES | | | SCAC4 |
| 66 | CLBI | CLINE, BILL TRANSPORTATION CO | | | SCAC3 |
| 67 | CLBJ | CALABRO, J TRANSPORT | | | SCAC3 |
| 68 | CLBK | CENTAUR LIQUID AND DRY BULK CO | | | SCAC3 |
| 69 | CLBL | CALABRIA LEASING INC | | | SCAC3 |
| 70 | CLBLO | C +L Consult & Logistik GmbH | | DE | VKM |
| 71 | CLBM | COLUMBIA MOVING & STORAGE INC | | | SCAC3 |
| 72 | CLBM | CHAMPAGNE LUMBER CO INC | | | SCAC4 |
| 73 | CLBN | CLIBURN TANK LINES INC | | | SCAC3 |
| 74 | CLBN | CLIBURN TANK LINES INC | | | SCAC4 |
| 75 | CLBO | COLUMBIA OIL COMPANY, THE | | | SCAC3 |
| 76 | CLBQ | COLUMBUS DISTRIBUTING CO INC | | | SCAC3 |
| 77 | CLBS | CARLIE BEADS | | | SCAC4 |
| 78 | CLBT | CLARK BROS. TRANSFER, INC | | | SCAC3 |
| 79 | CLBT | CLARK BROS TRANSFER, INC | | | SCAC4 |
| 80 | CLBU | CONTAINER LEASING A.G. | | | SCAC3 |
| 81 | CLBV | COLUMBIA TRANSPORT CORP | | | SCAC3 |
| 82 | CLBV | CLARKS BLUFF VAN LINES | | | SCAC4 |
| 83 | CLBX | Can-Lease Produce Transportation Ltd. | added 1/1972; eliminated 7/1974 | | NAKINA |
| 84 | CLBX | Can-Lease Produce Transportation Ltd. | added 1/72; eliminated 7/74 | | NRHS |
| 85 | CLBX | CAN-LEASE PRODUCE TRANSPORTATION LTD. | | | PWRC |
| 86 | CLBY | COLBY TRANSPORT | | | SCAC3 |
| 87 | CLBY | COLBY TRANSPORT | | | SCAC4 |
| 88 | CLC | Classic Air AG | Callsign: Classic Air, | CH | AVCODES |
| 89 | CLC | Columbia & Cowlitz Ry. Co. | 1/1975-7/2005 | | NAKINA |
| 90 | CLC | Columbia & Cowlitz Ry. Co. | 1/75-7/2000 | | NRHS |
| 91 | CLC | COLUMBIA & COWLITZ RAILWAY COMPANY | | | PWRC |
| 92 | CLC | Columbia and Cowlitz Railway | | | RSRV |
| 93 | CLC | Columbia and Cowlitz | | USA | TRAFFIC |
| 94 | CLCB | CLYDES CUSTOM BODY & PAINT | | | SCAC3 |
| 95 | CLCC | CLUTCH CARGO INTERNATIONAL INC | | | SCAC3 |
| 96 | CLCC | CLUTCH GLOBAL LOGISTICS | | | SCAC4 |
| 97 | CLCD | CALIFORNIA CONSOLIDATED ENTERPRISES | | | SCAC3 |
| 98 | CLCD | CL CONSOLIDATORS SERVICES LTD | | | SCAC4 |
| 99 | CLCF | CALICO FUELS INC | | | SCAC3 |
| 100 | CLCF | COOL CREEK FARM | | | SCAC4 |
