ABSTRACT
The aerospace industry is really not one industry but an assemblage of several that share an interest in producing aircraft, space vehicles and missiles. A comprehensive definition would include a manufacturing component, not only of the finished vehicles but also of the parts and systems which go into them, and components dealing with design (incorporating research and development or R&D) and maintenance. The US Labor Department attempted to distinguish the functions undertaken by the industry and concluded that they entailed the manufacture of aircraft, missiles, aeroengines, propellers and the propulsion, guidance and other systems associated with them. The Aerospace Industries Association of America (AIAA), the industry's trade body in the USA, has its own definition of the aerospace industry; namely, that activity engaged in research, development and manufacture of aircraft, missiles, space launch vehicles and spacecraft in the first place; the production of propulsion, guidance and control systems for the aforementioned in the second; and, finally, the procurement of whatever airborne and ground-based equipment is deemed necessary for the test, operation and maintenance of all aircraft and spacecraft. For the sake of brevity the first mentioned group—the airframe and engine functions—are termed Tier 1 activities, systems and parts manufacturers constitute Tier 2, whereas the support activities make up Tier 3.
