Torrejón Air Base was originally the home of the Spanish National Institute Aeronautics, however following the Pact of Madrid of 26 September 1953, construction began at Torrejón on a new 13,400-foot (4,100 m) concrete runway to replace the existing 4,266-foot (1,300 m) grass airstrip and on a massive concrete apron and other necessary maintenance and shelter facilities to accommodate the largest United States Air Force (USAF) bomber aircraft in the Strategic Air Command (SAC) inventory, with the base intended to support SAC Reflex missions.

Torrejón Air Base opened officially on 1 June 1957 with SAC activating the 3970th Strategic Wing on 1 July 1957.

The division also controlled the operations of numerous attached tactical fighter squadrons that were deployed to Spain for temporary duty (TDY).

Assigned or attached units of the division participated in numerous exercises with the Spanish Air Defense Command, and in some instances, with the U.S. Sixth Fleet.

In addition to the command and control mission, Torrejón Air Base hosted SAC reflex operations.

Reflex operations consisted of rotating B-47 Stratojet wings overseas for extended duty as part of a dispersal program.

Also, in this way SAC could spread out its potential as a Soviet target by placing its aircraft, weapons, and personnel on many more bases, with each bombardment wing having two additional installations to which it could disperse.

On 5 July 1958 the Air Defense Command's 497th Fighter-Interceptor Squadron arrived at Torrejón from Geiger AFB, Washington.

As well as the USAFE tactical aircraft, SAC retained a presence at Torrejón with the 98th Strategic Wing flying KC-135 Stratotankers from the base.

The 98th SW had no permanently assigned aircraft assigned, however CONUS-based SAC wings deployed aircraft to provide air refueling sup-port to meet the operational, alert, and exercise commitments of SAC, TAC, USAFE, and NATO in an area including the eastern Atlantic, most of Europe, North Africa and the Middle East.

As a result of the withdrawal of USAF forces in South Vietnam, on 15 July 1971 the 307th and 353rd TFS were returned to their home bases, and the 612th and 614th TFSs were assigned to Torrejón.

Operational squadrons were: As the time approached in 1987 for the renegotiation of the existing base agreement, which had entered into force in 1983 for a five-year period, pressures mounted for a reduction of the United States military presence in Spain.

[2] It was important to many Spaniards to eliminate vestiges of this history by converting Spain's long-standing bilateral relations with the United States into a multilateral undertaking through NATO.