C
- C.L.M.
- Campini
- CANSA
- Carden — UK
- Caunter
- Ceskoslovenska Zbrojovka
- CFM International (United States and France)
- Chamberlin
- Charomskiy
- Chelomey
- Chevrolet — U.S.
- Chotia
- Chrysler — U.S.
- Cicaré Aeronáutica
- Cieslak
- Cirrus — UK
- Cisco Motors
- Ader
- Clément-Bayard
- Clerget-Blin — France
- Coatalen
- Colombo
- Comet
- Commonwealth Aircraft Corporation — Australia
- Compact Radial Engines - Canada
- CNA - Italy
- Conrad
- Continental
- Cosmos Engineering Company
- Coventry-Victor — UK
- Crankless Engines Company
- Curtiss Aeroplane and Motor Company — U.S.
- Curtiss-Wright — U.S.
- Cuyuna Development Company - USA
Read more about this topic: List Of Aircraft Engine Manufacturers