Establishments primarily engaged in manufacturing or assembling complete aircraft. This industry also includes establishments owned by aircraft manufacturers and primarily engaged in research and development on aircraft, whether from enterprise funds or on a contract or fee basis. Also included are establishments engaged in repairing and rebuilding aircraft on a factory basis. Establishments primarily engaged in manufacturing engines and other aircraft parts and auxiliary equipment are classified in Industries 3724 and 3728; and those manufacturing guided missiles and space vehicles and parts are classified in Industry Group 376. Establishments primarily engaged in the repair of aircraft, except on a factory basis, are classified in Transportation, Industry 4581; and research and development on aircraft by establishments not owned by aircraft manufacturers are classified in Services, Industry 8731.