The first-generation jets gave way to all-weather dedicated interceptor jets. The F-94 Starfire was pressed into service as an "interim" interceptor, and North American in 1949 pushed an interceptor version of the Sabre, the F-86D. Despite the demands its complexity made upon a single pilot, the F-86D was backed by senior Air Force officials. Some 2,504 would be built and it would in time be the most numerous interceptor in the Air Defense Command fleet, with more than 1,000 in service by the end of 1955