During the height of the Cold War, the United States started to develop and expand its air defence capabilities to knock down Russian Air Force nuclear-armed bombers flying over the North Pole, across Canada, and into the northern United States to attack US military targets and major cities. The Air Defense Command created air command centres, radar stations, ground observer corps, and fighter-interceptor squadrons. The 54th Fighter-Interceptor Squadron (54th FIS), based at Ellsworth AFB, South Dakota, protected the Strategic Air Command's assets at Ellsworth AFB (nuclear alert bombers and tankers and intercontinental ballistic missiles). From 1951 to 1960, the men of the 54th FIS protected North America from possible air attack by long-range Russian Air Force bombers. The threat was deemed real at the time, only later shown to be less serious as the CIA overflew the Soviet Union with high-flying Lockheed U-2 reconnaissance aircraft.
