| Airline Name | ICAO | IATA | Callsign | Country |
| CAAC – Civil Aviation Administration of China | CCA | CA | China | |
| Cairo Aviation | CCE | AIR CAIRO | Egypt | |
| Cairo Charter & Cargo | Egypt | |||
| Cal Air International | CAI | EN | United Kingdom | |
| Caledonian – British United | BR | United Kingdom | ||
| Caledonian Airways | CKT | KT | United Kingdom | |
| Calm Air International | CAV | MO | Canada | |
| Cambodia Airlines | KHM | Y6 | Cambodia | |
| Cameroon Airlines | UYC | UY | Cameroon | |
| Cameroon Government | Cameroon | |||
| Canada – Transport Canada | TGO | GO | Canada | |
| Canada 3000 Airlines | CMM | 2T | ELITE | Canada |
| Canadian Airlines International | CDN | CP | Canada | |
| Canadian Armed Forces | CFC | Canada | ||
| Canadian Metro Airlines | Canada | |||
| Canadian North | MPE | 5T | EMPRESS | Canada |
| Canadian Pacific Airlines | CPC | CP | Canada | |
| Canadian Regional Airlines | CDR | KI | Canada | |
| Canafrica Transportes Aereos | NCR | KG | Spain | |
| Canair | CWW | Canada | ||
| Canarias Regional Air | CNM | Spain | ||
| Canjet Airlines | CJA | C6 | Canada | |
| Cape Air | KAP | 9K | United States | |
| Capital Airlines | CPG | BZ | United Kingdom | |
| Capital Cargo International Airlines | CCI | PT | CAPPY | United States |
| Capitol Airlines | CAP | CL | United States | |
| Cardig Air | Indonesia | |||
| Cardinal Lineas Aereas | Argentina | |||
| Cargair International | Congo, The Democratic Republic Of The | |||
| Cargo 360 | GGC | GG | LONG-HAUL | United States |
| Cargo Air | VEA | Bulgaria | ||
| Cargo Air Lines | ICL | 5C | Israel | |
| Cargo B Airlines | CBB | BB | CARGO-BEE | Belgium |
| Cargo Lion | TLX | Luxembourg | ||
| Cargoitalia | CRG | 2G | Italy | |
| Cargojet Airways | CJT | W8 | Canada | |
| Cargolux Airlines International | CLX | CV | Luxembourg | |
| Cargosur | OWS | Spain | ||
| Caribbean Airlines | BWA | BW | CARIBBEAN AIRLINES | Trinidad And Tobago |
| Caribbean Airways | IQQ | IQ | Barbados | |
| Caribbean Express | TLC | United States | ||
| Caribbean Star Airlines | GFI | 8B | CARIB STAR | Antigua And Barbuda |
| Caribbean Sun | SFG | ZQ | CARIB SUN | United States |
| Caribexpress | BCB | Barbados | ||
| Caribjet | CBJ | Antigua And Barbuda | ||
| Carnival Airlines | CAA | KW | United States | |
| Carpatair | KRP | V3 | Romania | |
| Cascade Airways | CCD | United States | ||
| Casino Express | CXP | XP | United States | |
| Caspian Airlines | CPN | RV | CASPIAN | Iran, Islamic Republic Of |
| Cathay Pacific | CPA | CX | CATHAY | Hong Kong |
| Cayman Airways | CAY | KX | Cayman Islands | |
| CC AIR | CDL | ED | United States | |
| CCM Airlines | CCM | XK | France | |
| CEBU Pacific Air | CEB | 5J | Philippines | |
| Ceiba Intercontinental | CEL | CEIBA LINE | Equatorial Guinea | |
| Celestair | Burkina Faso | |||
| Centavia | CNA | Serbia | ||
| Centennial Airlines | CNS | FA | Canada | |
| Centennial Airlines | CNA | BE | Spain | |
| CentrAfrique Air Express | CAE | 6C | EXPRESS CENTRAF | Central African Republic |
| Central Mountain Air | GLR | 9M | Canada | |
| Centralwings | CLW | C0 | CENTRALWINGS | Poland |
| Centurion Air Cargo | CWC | WE | United States | |
| Chabahar Airline | IRU | Iran, Islamic Republic Of | ||
| Chalair | CLG | M6 | France | |
| ChallengAir | CHG | 1I | Belgium | |
| Challenge Air Cargo | CWC | WE | United States | |
| Challenge International Airlines | OFF | United States | ||
| Champion Air | CCP | MG | CHAMPION AIR | United States |
| Chanchangi Airlines | NCH | 3U | Nigeria | |
| Chang An Airlines | CGN | 2Z | China | |
| Channel Express | EXS | LS | CHANNEX | United Kingdom |
| Charlotte AcL | United States | |||
| Chartair | United Kingdom | |||
| Chartwell Aircraft Company | United States | |||
| Chautauqua Airlines | CHQ | RP | CHAUTAUQUA | United States |
| CHC Airways | SCH | AW | Netherlands | |
| Cheboksary Air Enterprise | CBK | Russian Federation | ||
| CHeights | Malaysia | |||
| Chilean Air Force | Chile | |||
| China Airlines | CAL | CI | DYNASTY | Taiwan |
| China Cargo Airlines | CKK | CK | CHINA KING | China |
| China Eastern Airlines | CES | MU | CHINA EASTERN | China |
| China Express Airlines | HXA | G5 | CHINA EXPRESS | China |
| China General Aviation Corp. CGAC | CTH | GP | China | |
| China National Aviation Corporation (CNAC) | CAG | F6 | China | |
| China Northern Airlines | CBF | CJ | China | |
| China Northwest Airlines | CNW | WH | CHINA NORTHWEST | China |
| China Postal Airlines | CYZ | China | ||
| China Southern Airlines | CSN | CZ | CHINA SOUTHERN | China |
| China Southwest Airlines | CXN | SZ | China | |
| China United Airlines | CUA | KN | LIANHANG | China |
| China West Air | CHB | PN | WEST CHINA | China |
| China Xinhua Airlines | CXH | XW | China | |
| China Xinjiang Airlines | CXJ | XO | China | |
| China Yunnan Airlines | CYH | 3Q | YUNNAN | China |
| Chongqing Airlines | CQN | OQ | CHONG QING | China |
| Chrysler Pentastar Aviation | CYL | United States | ||
| Ciao Fly | CIO | Italy | ||
| Cielos del Peru | CIU | A2 | Peru | |
| Cimber Air | CIM | QI | Denmark | |
| Cimber Sterling | CIM | QI | CIMBER | Denmark |
| CIP Transports | France | |||
| Cirrus Air | NTS | United States | ||
| Cirrus Airlines | RUS | C9 | Germany | |
| Cirrus Middle East | JTI | Lebanon | ||
| Citelynx Travel | United Kingdom | |||
| Citilink Garuda Indonesia | GIA | GA | Indonesia | |
| City Air | CIP | 6E | Germany | |
| City Airline | SDR | CF | Sweden | |
| City Bird | CTB | H2 | Belgium | |
| City Bird France | CFB | France | ||
| City Star Airlines | ISL | X9 | ISLANDIA | United Kingdom |
| Cityflyer Express | CFE | FD | FLYER | United Kingdom |
| Cityjet | BCY | WX | CITY IRELAND | Ireland |
| Cityline Hungary | CNB | Hungary | ||
| CL Air | Netherlands | |||
| Click Mexicana | CBE | QA | CLICK | Mexico |
| Clickair | AIS | XG | Spain | |
| Club 328 | SDJ | SPACEJET | United Kingdom | |
| Club Air | ISG | 6P | Italy | |
| Club Airways | United Kingdom | |||
| Club Excellence Corporation | United States | |||
| CNA | United States | |||
| Coast Air | CST | BX | COAST CENTRE | Norway |
| Colgan Air | CJC | 9L | United States | |
| Colombian Government | Colombia | |||
| Color Air | CLA | Norway | ||
| Comair | CAW | MN | South Africa | |
| COMCO | United States | |||
| Comlux Aviation | CLA | COMLUX | Switzerland | |
| Command Airways | United States | |||
| Community Airlines | CML | COMMUNITY | Tanzania, United Republic Of | |
| CommutAir (Continental Connection) | UCA | C5 | COMMUTAIR | United States |
| Comoro Islands Airline | Comoros | |||
| Compagnie Aérienne du Mali (CAM) | CMM | CAMALI | Mali | |
| Compagnie Africaine d’Aviation CAA | Congo, The Democratic Republic Of The | |||
| Companhia Vale do Rio Doce | Brazil | |||
| Compania Aerea Canaria de Transporte Aereo | CCU | Spain | ||
| Compaq Computer | United States | |||
| Corp | ||||
| Compass Airlines | CYM | YM | Australia | |
| Compass Airlines (Northwest Airlink) | United States | |||
| Conair | OYC | OY | Denmark | |
| Condor | CFG | DE | Germany | |
| Condor Berlin | CIB | DE | Germany | |
| Congo Airlines (CAL) | ALX | EO | ALLCONGO | Congo, The Democratic Republic Of The |
| Consolidated Contractors Company | United States | |||
| Constellation International Airlines | CIN | CQ | CONSTELLATION | Belgium |
| Contact Air | KIS | C3 | CONTACTAIR | Germany |
| Conti-Flug | Germany | |||
| Continent Air Paris | France | |||
| Continental Air Lines | COA | CO | CONTINENTAL | United States |
| Continental Express | BTA | United States | ||
| Continental Lite | United States | |||
| Continental Micronesia | CMI | CS | Guam | |
| Continental West Airlines | CO | United States | ||
| Continental Wings -Comoros Airlines | CWK | Comoros | ||
| Conviasa | VCV | V0 | CONVIASA | Venezuela |
| COPA | CMP | CM | COPA | Panama |
| Corendon Airlines | CRD | Turkey | ||
| Corporate Aircraft Company | CPO | United States | ||
| Corporate Express | CPB | 2 | PENTA | Canada |
| Corporate Jets | CJI | United States | ||
| Corsair | CRL | SS | CORSAIR | France |
| Corse Air | France | |||
| Corse Mediterranee | CCM | ZN | France | |
| Cosmic Air | COZ | F5 | COSMIC AIR | Nepal |
| Cosmos Air | AZE | ZE | Germany | |
| Costa Rican Skies | Costa Rica | |||
| CP Air | CPC | CP | Canada | |
| CR Airways | CRK | Hong Kong | ||
| Crescent Air Transport | KJ | Pakistan | ||
| Cretan Airlines | KRT | C5 | Greece | |
| Croatia Airlines | CTN | OU | CROATIA AIRLINES | Croatia |
| Cronus Airlines | CUS | X5 | Greece | |
| Crossair | CRX | LX | Switzerland | |
| Cruzeiro | CRZ | SC | Brazil | |
| CTA | CTA | Switzerland | ||
| Cubana | CUB | CU | Cuba | |
| Curaçao Express | Netherlands Antilles | |||
| CuraçaoExel | Netherlands Antilles | |||
| Cygnus Air | RGN | XG | Spain | |
| Cyprus Airways | CYP | CY | CYPRUS | Cyprus |
| Cyprus Turkish Airlines (KTHY) | KYV | YK | AIRKIBRIS | Turkey |
| Czech Air Force | CEF | Czech Republic | ||
| Czech Airlines (CSA) | CSA | OK | Czech Republic |