3728  Aircraft Parts and Auxiliary Equipment, Not Elsewhere Classified

Establishments primarily engaged in manufacturing aircraft parts and
auxiliary equipment, not elsewhere classified. This industry also includes
establishments owned by manufacturers of aircraft parts and auxiliary
equipment and primarily engaged in research and development on aircraft
parts, whether from enterprise funds or on a contract or fee basis.
Establishments primarily engaged in manufacturing or assembling complete
aircraft are classified in industry 3721; those manufacturing aircraft
engines and parts are classified in industry 3724; those manufacturing
aeronautical instruments are classified in industry 3812; those
manufacturing aircraft engine electrical (aeronautical electrical)
equipment are classified in industry 3694; and those manufacturing guided
missile and space vehicle parts and auxiliary equipment are classified in
industry 3769. Establishments not owned by manufacturers of aircraft parts
but primarily engaged in research and development on aircraft parts on a
contract or fee basis are classified in Services, industry 8731.