The first F-106A's were delivered to the Air Force on May 1, 1959 to the Air Defense Command's 539th Fighter Interceptor Squadron at McGuire AFB in New Jersey, replacing the F-86L.
The first operational unit to fly the F-106 was the 498th FIS at Geiger AFB in Washington on 29 May 1959, no less than five years later than originally planned. Even then, numerous problems kept the Delta Dart from being declared fully operational for another 5 months until October 31, 1959. The remaining squadrons were re-equipped with the F-106A by the end of 1960.
ADC squadrons began converting from their previous air frames of F-102's and F-86L's to the F-106 at about 1 squadron per month beginning that May 1959.
Challenges were great! There were no F-106B models available to squadrons for one to two months AFTER the A models arrived, making pilot checkout difficult.
The MA-1 Technical School at Lowery AFB, CO was nearly a year long, making it difficult to acquire qualified skilled MA-1 technicians early on. And the MA-1 AGE equipment was extremely complex, more-so than the previous motor-pool maintenance personnel were used to working with.
The first Air National Guard unit to receive the F-106 was the 186th FIS of the Montana ANG, based at Great Falls, which took delivery of its first planes on April 3, 1972. Six ANG units flew the F-106 on Air Defense Command mission.
The last Delta Dart-equipped squadron, the 119th FIS at Atlantic City, New Jersey flew its final alert duty on July 7, 1988. It the last ANG unit to fly the Delta Dart, which sent its last plane to AMARC (the dreaded Boneyard in AZ) in August of 1988.