[citation needed] Most of its facilities are operated by private contractors to build and maintain military aircraft and their components for the United States and its allies.

[citation needed] NASA's Dryden Flight Research Facility at Edwards Air Force Base was where the spacecraft was loaded and unloaded on a Shuttle Carrier Aircraft.

[citation needed] The structures of the orbiter were manufactured at various companies under contract to Rockwell International's Space Transportation Systems Division, Downey, California.

The upper and lower forward fuselage, crew compartment, forward reaction control system and aft fuselage were manufactured at Rockwell's Space Transportation Systems Division facility in Downey and were transported overland from Downey to Rockwell's Palmdale, California, assembly facility.

[citation needed] The midfuselage was manufactured by General Dynamics, San Diego, California, and transported overland to Rockwell's Palmdale assembly facility.

The vertical tail (including rudder/speed brake) were manufactured by Fairchild Republic in Farmingdale, Long Island, New York, and transported overland to Rockwell's Palmdale assembly facility.

[citation needed] The aft orbital maneuvering system/reaction control system pods were manufactured by McDonnell Douglas, St. Louis, Missouri, and transported by aircraft to Rockwell's Palmdale assembly facility.

[citation needed] The National Aeronautics and Space Administration had been paying the Air Force for use of Plant 42 facilities for the shuttle work.

The outbreak of the Korean War in 1950 caused the Air Force to reactivate the property for use in final assembly and flight testing of military jet aircraft.

[citation needed] The concept for Air Force Plant 42 originated in the challenge of flight testing high performance jet aircraft over heavily populated areas.

Following approval of the Master Plan in 1953, the Palmdale Airport officially became Air Force Plant 42; ownership of the installation was transferred to the Federal Government in 1954.

[citation needed] With USAF encouragement, Lockheed, looked upon with favor by the Air Force at this time, established its permanent presence at Plant 42.

[citation needed] Since then, the plant has supported facilities for the production, engineering, final assembly and flight testing of high performance aircraft.