C
- C. Itoh, C. Itoh & Co – Japan, (1955–1970) > JAMCO
- CAARP, Cooperatives des Ateliers Aéronautiques de la Région Parisienne – France
- CAB, Constructions Aéronautiques du Béarn – France
- Cable-Price, Cable-Price Corporation – New Zealand
- Cabrinha, Cabrinha Aircraft Corporation – United States
- Cabrinha, Cabrinha Engineering Inc – United States
- CAC, Commonwealth Aircraft Corporation Pty Ltd – Australia
- CAG, Construcciones Aeronáuticas de Galicia – Spain
- Caldas Aeronautica, Pali, Colombia
- Calipt'Air, Spiez, Switzerland
- Callair, Call Aircraft Company – United States, (1939–1959) > IMCO
- Callair, Callair Inc – United States
- Calumet, Calumet Motorsports Inc – United States
- Camair, Camair Aircraft Corporation – United States
- Camair, Camair Division of Cameron Iron Works Inc – United States
- CAMCO, Central Aircraft Manufacturing Company – China, CAMCO
- Cameron (1), Cameron Balloons Ltd – United Kingdom, (1970–present)
- Cameron (2), Cameron & Sons Aircraft – United States
- Campana, Campana Aviation – France
- CAMS, Chantiers Aéro-Maritimes de la Seine – France
- CAMS, Cairns Development Company – United States, (or Cairns Aircraft (E. B. Cams))
- Calumet Motorsports, Lansing, Illinois, United States
- Canada Air RV, Canada Air RV Inc – Canada
- Canadair, Bombardier Aerospace Canadair – Canada, (?-1986) > Bombardier Aerospace
- Canadair, Canadair Group of Bombardier Inc – Canada
- Canadair, Canadair Inc – Canada
- Canadair, Canadair Ltd – Canada
- Canadian Aeroplanes, Canadian Aeroplanes Ltd. – Canada
- Canadian Car & Foundry, Canadian Car & Foundry Co. – Canada
- Canadian Home Rotors, Canadian Home Rotors Inc – Canada
- Canadian Vickers, Canadian Vickers Ltd – Canada
- Canard Aviation – Switzerland
- CANSA, Cansa – Italy
- CANT, Cantiere Navale Triestino – Italy, (?-1931) > CRDA
- CAO/SNCAO, Societe Nationale de Construction Aeronautique de l'Ouest – France
- CAP – Companhia Aéronautica Paulista – Brazil
- CAP Aviation, CAP Aviation – France
- Capella, Capella Aircraft Corporation, Austin, Texas, United States
- Caproni, Caproni – Italy, (1908–1983) > Agusta
- Caproni Vizzola, Caproni Vizzola Costruzione Aeronautiche SpA – Italy
- Carlson, Carlson Aircraft Inc – United States
- CARMAM, Coopérative d'Approvisionnement et de Réparation de Matériel Aéronautique de Moulins – France
- Carplane GmbH, Braunschweig, Germany
- Carriou, Louis Carriou – France
- Carstedt, Carstedt – United Kingdom
- Cartercopters, CarterCopters LLC – United States
- CASA, Construcciones Aeronáuticas SA – Spain
- Caspar, Caspar-Werke – Germany
- Cassutt, Thomas K. Cassutt – United States
- CATA, Construction Aéronautique de Technologie Avancée – France
- Caudron, British Caudron Co Ltd. – United Kingdom, (Last aircraft made in 1919, went into receivership 1924.)
- Caudron, Caudron – France, (1909–?)
- Cavalier, Cavalier Aircraft Corp. – United States, (?-1971) > Piper Aircraft
- CCF, Canadian Car & Foundry Company Ltd – Canada
- CEI, CEI – United States
- Celier Aviation, CA – Poland
- Celair, Celair (Pty) Ltd – South Africa
- Centrair, SA Centrair – France
- Central Aircraft Company, Central Aircraft Company Limited – United Kingdom
- Centrala Flygverkstaden Malmslätt (CFM) – Sweden
- Centrala Verkstaden Malmslätt (CVM) – Sweden
- Centre Est, Centre Est Aéronautique – France
- Century, Century Aircraft Corporation – United States
- CERVA, Consortium Européen de Réalisation et de Vente d'Avions GIE – France
- Cessna, Cessna Aircraft Company – United States, (1927–present)
- Cessna-Roos, Cessna-Roos Aircraft Company – United States, (1927) > Cessna Aircraft
- Clyde Cessna, Clyde Cessna – United States, (1911) (Clyde Vernon Cessna) > Travel Air
- Cessna-Reims, Cessna-Reims – United States/France
- CFA, Compagnie Française d'Aviation – France
- CFM, CFM Aircraft Ltd – United Kingdom
- CFM, Cook Flying Machines, CFM Metal Fax Ltd – United Kingdom
- CFM Air, Ciriè, Italy
- CGS Aviation, Grand Bay, Alabama, United States
- Chadwick, Chadwick Helicopters – United States
- Chalard, Jacques et Renée Chalard – France
- Champion, Champion Aircraft Company Inc – United States, (1954–1970) > Bellanca
- Champion, Champion Aircraft Corporation – United States
- Chance Vought, Chance Vought Aircraft Inc – United States, (1922–1961) > Vought
- Chance Vought, Chance Vought Corporation – United States
- Changhe, Changhe Aircraft Factory – China
- Changhe, Changhe Aircraft Industries Corporation – China
- Changhe, Changhe Aircraft Manufacturing Corporation – China
- Chasle, Yves Chasle – France
- Chayair, Chayair Manufacturing and Aviation – South Africa
- Chengdu, Chengdu Aircraft Industrial Corporation – China
- Chernov, Opytnyi Konstruktorskoye Byuro Chernov B & M OOO – Russia
- Chetverikov, Chetverikov – Russia, (Igor Vyacheslavovich Chetverikov)
- Chichester-Miles, Chichester-Miles Consultants Ltd – United Kingdom
- Chilton, Chilton Aircraft – United Kingdom, (1937–?)
- Chincul, Chincul SACAIFI – Argentina
- Chris Tena, Chris Tena Aircraft Association – United States
- Chrislea, Chrislea Aircraft Co. Ltd. – United Kingdom
- Christen, Christen Industries Inc – United States
- Chu, Major General C.J. Chu – Republic of China
- Cicaré, Cicaré Helicópteros SA – Argentina
- Cierva, Cierva Autogyro Company – United Kingdom, (Juan de la Cierva)
- Circa, Circa Reproductions – Canada
- Cirrus, Cirrus Design Corporation – United States, (1984–present)
- Citroen-Marchetti, Citroen-Marchetti – France
- Civil Aviation Department of India – India
- Claassen, Claassen – United States
- CLASS, Canadian Light Aircraft Sales and Services Inc – Canada
- Classic, Classic Aircraft Corporation (WACO Classic Aircraft Corporation) – United States
- Classic Fighter, Classic Fighter Industries Inc – United States
- Classic Sport, Classic Sport Aircraft – United States
- Claudius Dornier, Claudius Dornier Seastar GmbH & Co KG – Germany
- Claxton High School – United States
- Clément-Bayard – France
- Clifford Aeroworks, Clifford Aeroworks – United States
- Cligent Aerospace – India
- Clutton, Eric Clutton – United Kingdom
- CMASA, Costruzioni Meccaniche Aeronautiche Società Anonima – Italy
- CNA, Compagnia Nazionale Aeronautica – Italy
- CNIAR, Centrul National al Industriei Aeronautice Române – Romania
- CNNA, Companhia Nacional de Navegação Aérea – Brazil
- Coandă, Henri Coandă – Romania, (1910–1911) (Henri Marie Coandă) > Bristol
- COBELAVIA, Compagnie Belge d'Aviation – Belgium
- Cobra, Cobra Aviation – Australia, (2000–present)
- Cody, Samuel Cody – United Kingdom, (Samuel Franklin Cody)
- Colemill, Colemill Enterprises Inc – United States
- Collins, Collins Aero – United States
- Colomban, Michel Colomban – France
- Colombia, Columbia Aircraft Company – United States
- Colonial, Colonial Aircraft Corporation – United States
- COMAC, Commercial Aircraft Corporation of China – China (2008–present)
- Commander, Commander Aircraft Company – United States
- Commonwealth (1), Commonwealth Aircraft Corporation Pty Ltd – Australia, see CAC
- Commonwealth (2), Commonwealth Aircraft Corporation Inc – United States, (1942–1947)
- Comper, Comper Aircraft Co. Ltd. – United Kingdom, (1929–?)
- Comte, Comte Aircraft Factory – Switzerland
- Conair, Conair Group Inc. – Canada
- Condor Powered Parachutes, Nicholson, Georgia, United States, (later called Southern Powered Parachutes)
- Conroy, Conroy Aircraft Corporation – United States
- Consolidated Aeronautics Corporation – manufactured Lake aircraft in the 1960s–70s – United States
- Consolidated, Consolidated Aircraft Corporation – United States
- Continental Copters, Continental Copters Inc – United States
- Convair, Consolidated-Vultee Aircraft Corporation – United States, (1943–1996) > General Dynamics
- Convair, Convair Division of General Dynamics Corporation – United States
- Corben Sport Plane and Supply Company (US) – founded 1931, sold to Paul Poberezny in 1952
- Corby, John C. Corby – Australia
- Cosy, Cosy Europe – Germany
- Country Air, Country Air Inc – United States
- Coupe, Coupé-Aviation – France
- Cox-Klemin, Cox-Klemin Aircraft Corporation – United States
- Co-Z, Co-Z Development Corporation – United States
- Co-Z, Co-Z Europa – Germany
- Crae, CRAE Elettromeccanica SpA – Italy
- Craiova, Intreprinderea de Avioane Craiova – Romania
- Cranfield (1), Cranfield Aeronautical Services – United Kingdom
- Cranfield (2), Cranfield Institute of Technology, College of Aeronautics – United Kingdom
- CRDA, Cantiere Riuniti dell'Adriatico – Italy (1931–?)
- Creative Flight, Creative Flight Inc – Canada
- Croses, Emilien Croses – France
- CSS, Centralne Studium Samolotów – Poland
- CTRM, Composites Technology Research Malaysia Sdn Bhd – Malaysia
- Cub, Cub Aircraft Company – Canada
- Cub Crafters, Cub Crafters Inc – United States
- Culp, Culps Specialties – United States
- Culver, Culver Aircraft Company – United States
- Cunliffe-Owen, Cunliffe-Owen Aircraft – United Kingdom
- Curtiss, Curtiss-Wright Corporation – United States, (1929–present)
- Curtiss Aeroplane and Motor Company, Curtiss Aeroplane and Motor Company – United States, (1909–1929) > Curtiss-Wright
- Curtiss-Reid Aircraft Ltd., Curtiss-Reid Aircraft Ltd. – Canada
- Custer Channel Wing Corporation, Hagerstown, Maryland – United States
- Custom Flight, Custom Flight Components Ltd – Canada
- Custom Flight Limited, Tiny, Ontario, Canada
- Cvjetkovic, Anton Cvjetkovic – United States
- C.W. Aircraft Ltd – United Kingdom > General Aircraft Ltd
- CWL, Centralne Warsztaty Lotnicze – Poland
- CZAW, Czech Aircraft Works SRO – Czech Republic
- Cyclone Manufacturing Inc., Mississauga, Ontario, Canada (Aerospace Parts Manufacturing)
- CZL, Centralne Zaklady Lotnicze – Poland, (Central Aviation Establishment)