 The Maryland Air National Guard was not federalized, however its aircraft were replaced by very long distance F-51H Mustangs in 1951 to better carry out its air defense mission.By 1955 the Mustangs were at the end of their operational lifetime, and the Air Force issued a directive to ADC to replace all of its interceptor force with Jet Aircraft.As a result, the 104th entered the jet age and received Korean War veteran F-86E Sabres to replace its propeller-driven Mustangs, which were retired.