| CAA | EV | 862 | Atlantic Southeast Airlines |
| CAG | China National Aviation Corporation | ||
| CAI | Corendon Airlines | ||
| CAL | CI | 297 | China Airlines |
| CAV | MO | 622 | Calm Air International ltd |
| CAW | MN | 161 | Kulula.com |
| CAY | KX | 378 | Cayman Airways |
| CBE | QA | 723 | Aerovias Caribe |
| CBF | CJ | 782 | China Northern Airlines |
| CBI | Cabi Airlines | ||
| CBK | Cheboksary Air Enterprise | ||
| CBM | Cherokee Express | ||
| CCA | CA | 999 | Air China |
| CCI | PT | Capital Cargo International Airlines | |
| CCL | Continental Aviation/Analinda | ||
| CCM | XK | 146 | Compagnie Corse Mediterranee |
| CCP | MG | Champion Air | |
| CCX | CCI | ||
| CCY | Cherry-Air | ||
| CDG | SC | 324 | Shandong Airlines |
| CDL | ED | 354 | CCAIR (USAirExpress) |
| CDN | CP | 018 | Canadian Airlines International |
| CDO | 7G | 513 | Cargo d´Or |
| CDR | Canadian Regional Airlines | ||
| CDS | Central Districts Airline | ||
| CEE | C-Air | ||
| CES | MU | 781 | China Eastern Airlines |
| CET | GC | Centrafrican Airlines | |
| CEX | CE | Capitol Air Express | |
| CFA | China Flying Dragon Aviation | ||
| CFE | FD | 844 | Cityflyer |
| CFG | DE | 881 | Condor |
| CFJ | IV | 791 | Fujian Airlines |
| CFP | CF | Faucett Peruvian Airlines | |
| CFR | Chauffair | ||
| CFS | EM | 464 | Empire Airlines |
| CGH | CZ | Guizhou Airlines | |
| CGK | C4 | 094 | Click Airways |
| CGL | Seagle Air | ||
| CGN | 2Z | Chang´an Airlines | |
| CGP | 8L | Cargo Plus Aviation | |
| CGT | CNG Transavia | ||
| CGW | G8 | Air Great Wall | |
| CHB | H6 | Chelyabinsk Air Enterprise | |
| CHF | X7 | 637 | Chita Avia |
| CHG | Challengair | ||
| CHH | HU | 880 | Hainan Airlines |
| CHJ | Air Chakya | ||
| CHP | 6A | 095 | AVIACSA- Consorcio Aviaxsa SA de CV |
| CHQ | US | 363 | Chautauqua Airlines Inc (USAir Express) |
| CHR | Air Charter Service (Zaire) | ||
| CIF | Caribbean Flights | ||
| CIM | QI | 647 | Cimber Air A/S |
| CIR | Arctic Circle Air Service | ||
| CIS | CIS Express Airlines | ||
| CIU | A2 | 529 | Cielos Airlines |
| CJA | Canjet Airlines | ||
| CJG | F6 | Zhejiang Airlines | |
| CJT | W8 | 489 | Cargojet Airways |
| CKK | CK | 112 | China Cargo Airlines |
| CKS | K4 | 272 | Kalitta Air |
| CKT | KT | Caledonian Airways | |
| CLH | CL | 683 | Lufthansa CityLine |
| CLT | XC | 918 | Air Caribbean |
| CLW | C0 | Centralwings | |
| CLX | CV | 172 | Cargolux Airlines |
| CMI | CS | 596 | Continental Micronesia |
| CMM | I5 | Compagnie Aerienne du Mali | |
| CMP | CM | 230 | COPA Airlines |
| CNA | BE | Centennial Airlines | |
| CNJ | 3W | Nanjing Airlines | |
| CNO | SK | SAS Braathens ASA | |
| CNW | WH | 783 | China Northwest Airlines |
| CNX | All Canada Express | ||
| COA | CO | 005 | Continental Airlines |
| COM | OH | 886 | Comair - Delta Connection |
| COU | C4 | Airlines of Carriacou | |
| COY | 7C | 575 | Coyne Airways |
| COZ | F5 | 447 | Cosmic Air |
| CPA | CX | 160 | Cathay Pacific Airways |
| CPH | Champagne Airlines | ||
| CPI | 5J | 203 | Cebu Pacific Air |
| CPN | RV | 879 | Caspian Air Lines |
| CPT | DN | Corporate Air | |
| CQH | 9S | 089 | Spring Airlines |
| CRC | Conair Aviation | ||
| CRF | OR | 107 | Crimea Air |
| CRG | 2G | 002 | Cargoitalia |
| CRK | N8 | 851 | Hong Kong Airlines Ltd |
| CRL | SS | 923 | Corsair |
| CRN | 7L | 164 | Aero Caribbean |
| CRQ | YN | 219 | Air Creebec (1994) |
| CRW | 2R | 809 | Regal (Crownair) |
| CRZ | SC | Cruizeiro (Servicos Aereos Cr. Do Sol) | |
| CSA | OK | 064 | Czech Airlines |
| CSC | 3U | 876 | Sichuan Airlines |
| CSH | FM | 774 | Shanghai Airlines |
| CSN | CZ | 784 | China Southern Airlines |
| CSQ | II | 175 | IBC Airways Inc |
| CST | BX | 970 | Coast Air AS |
| CSW | World Wide Air Charter Systems | ||
| CSZ | 4G | 479 | Shenzhen Airlines |
| CTB | H2 | City Bird Airlines | |
| CTH | China General Aviation | ||
| CTL | Central Airlines | ||
| CTN | OU | 831 | Croatia Airlines |
| CTP | PQ | Tashkent Aviation Production Association | |
| CTT | DG | 373 | Custom Air Transport |
| CTY | Century Airlines | ||
| CUA | China United Airlines | ||
| CUB | CU | 136 | Cubana |
| CUS | X5 | Cronus Airlines | |
| CVC | J7 | 601 | Centre-Avia Airlines |
| CWC | WE | 307 | Centurion Air Cargo |
| CWU | WU | Wuhan Airlines | |
| CWW | WW | CanAir Cargo | |
| CXA | MF | 731 | Xiamen Airlines |
| CXH | X2 | Xinhua Airlines | |
| CXI | 8C | Shanxi Airlines | |
| CXJ | XO | 651 | Xinjiang Airlines |
| CXN | SZ | 785 | China Southwest Airlines |
| CXP | XP | Casino Express | |
| CXT | DQ | 457 | Coastal Air Transport |
| CYH | 3Q | 592 | Yunnan Airlines |
| CYM | 612 | Compass Airlines | |
| CYN | Z2 | Zhong Yuan Airlines | |
| CYP | CY | 048 | Cyprus Airways |
| CYZ | PO | China Postal Airlines |