C
- California Central Airlines
- CalPac (California Pacific) (1993 - 1995 to Mesa Airlines)
- Cal Sierra Airlines (1980)
- Cal State Airlines
- Cape Smythe Air (1975 - 2005, to Frontier Flying Service)
- Capital Air Service (1966 - 1989)
- Capital Airlines (1936 - 1961, to United Airlines)
- Capital Cargo International Airlines
- Capitol Air Lines (1970s - 1980s)
- Capitol Airways (1946 - 1982)
- Cargo 360 (2005 - 2008, to Southern Air)
- Cardinal Airlines
- Caribbean Sun (2002 - 2007)
- Carnival Air Lines (1988 - 1998, to Boston-Maine Airways)
- Cascade Airways (1969 - 1986)
- Catalina Airlines (1940 - 1969)
- CCAir (1987 - 2002)
- Centennial Airlines (1981 - 1987)
- Central Airlines (1944 - 1967)
- Challenge Air Cargo (1978 - 2001)
- Champion Air (1995 - 2008; ceased operations on May 31, 2008)
- Chicago Air (1985 - 1986)
- Chicago and Southern Air Lines (1934 - 1953)
- Chicago Express Airlines (1993 - 2005)
- Coastal Airways (1929 - 1930)
- Cochise Airlines (1971 - 1982)
- Colgan Airways (1971 - 1986, to Presidential Airways, revived 1991, and currently operating as Continental Express, United Express, and US Airways Express: see http://www.colganair.com)
- Colonial Air Transport (1926 - 1930)
- Comair (1977-2012)
- Command Airways
- Conquest Airlines (1988 - 1997)
- Conquest Sun Airlines (to AirTran Airways)
- Continental Airlines (1934 - 2012, to United Airlines)
- Continental Micronesia (1968 - 2011, to United Airlines)
- Crown Airways (1969 - 1992 to Mesa Airlines)
- Curtiss Flying Service (1929 - 1932)
Read more about this topic: List Of Defunct Airlines Of The United States