The Aerospace and Defense category comprises industries and establishments primarily engaged in one or more of the following:
Development, manufacture, and distribution of civil and military aircraft, missiles, space vehicles, military equipment, and the auxiliary equipment, parts and supplies.
Development, manufacture, and distribution of aerospace engines, propulsion units, and auxiliary equipment or parts.
Development and production of aerospace and military product prototypes.
Aircraft conversion (i.e., major modifications to systems).
Complete aircraft or propulsion systems overhaul and rebuilding (i.e., periodic restoration of aircraft to original design specifications).
Services that specifically support these industries (e.g., consulting, marketing, associations, etc.).
In general, the aerospace industry is engaged in the research, development, and manufacture of flight vehicles, ranging from unpowered gliders, sailplanes and lighter-than-air craft up though space vehicles. The term aerospace is derived from the words aeronautics and spaceflight.