The F-106 Delta Dart is a supersonic, all-weather interceptor. Originally envisioned as an advanced derivative of the F-102A Delta Dagger and given the designation F-102B, the "Ultimate Interceptor", as it was known, entailed such extensive changes that in June, 1956, the designation was changed to F-106. It was designed from the ground up as an Interceptor and nothing but an interceptor.
Originally designated the F-102B, it was re-designated the F-106 due to it's extensive structural changes and the more powerful Pratt & Whitney J57 engine. The single seat F-106A first flew on December 26, 1956, was delivered to and entered operational service with the US Air Force (USAF) in May 1959 and achieved initial operational capability in October, 1959. The two-seat F-106B made its maiden flight on April 9, 1958, achieved initial operational capability in July 1960, and retained the full combat capability of the F-106A. All F-106 production ended in late 1960 with a total of 277 F-106A's and 63 F-106B's being built at a cost of about $5 million each."
