 It served on active duty with the United States Air Force Air Defense Command (and successor organizations) and Air Defense squadrons of the Air National Guard for almost 30 years, much longer than most of its contemporaries.Originally designated the F-102B, it was redesignated F-106 because of extensive structural changes and a more powerful engine.The first F-106A flew on 26 December 1956, and deliveries to the USAF began in July 1959 with the 539th Fighter-Interceptor Squadron at McGuire AFB, New Jersey.