| American Helicopter Co; Div of Fairchild Aircraft | Hagerstown, | Maryland, | USA |
| Bell Helicopter Corporation | Fort Worth, | Texas, | USA |
| Bell Helicopter Division of Bell Aircraft Corp | Greenville, | New York, | USA |
| Bell Helicopter Textron Inc | Fort Worth, | Texas, | USA |
| Bensen Aircraft Corporation | Raleigh-Durham, | North Carolina, | USA |
| Boeing Vertol | Philadelphia, | Pennsylvania, | USA |
| Brantly Helicopter Corp | Frederick, | Oklahoma, | USA |
| Bristol Aeroplane Company | Filton, | England, | UK |
| Cessna Aircraft Company | Wichita, | Kansas, | USA |
| Focke-Achgelis & Co GmbH | Hoyenkamp, | Lower Saxony, | Germany |
| Gyrodyne Company of America | Saint James, | New York, | USA |
| Hiller Helicopters | Firebaugh, | California, | USA |
| Hughes Helicopters | Culver City, | California, | USA |
| Kaman Aircraft Corporation | Bloomfield, | Connecticut, | USA |
| Kamov Design Bureau (Ka) | Moscow, | | Russia |
| Kellett Autogyro Corporation | Willowgrove, | Pennsylvania, | USA |
| Lockheed Aircraft Corporation | Burbank, | California, | USA |
| McCulloch Aircraft Corporation | Milwaukee, | Wisconsin, | USA |
| McDonnell Douglas Corporation | St Louis, | Missouri, | USA |
| Mil Design Bureaue (Mi) | Moscow, | | Russia |
| Nash-Kelvinator Corporation | Detroit, | Michigan, | USA |
| Piasecki Helicopter Corporation | Morton, | Pennsylvania, | USA |
| Sikorsky Aircraft Div of United Technologies Corp | Stratford, | Connecticut, | USA |
| Westland Aircraft | Yeovil, | England, | UK |
| Westland Helicopters | Yeovil, | England, | UK |
| Yakovlev Design Bureau JSC (YAK) | Moscow, | N Admin Okrug, | Russia |
