 In the late 1960s, Boyd gathered a group of like-minded innovators who became known as the Fighter Mafia, and in 1969, they secured Department of Defense funding for General Dynamics and Northrop to study design concepts based on the theory.Air Force F-X proponents remained hostile to the concept because they perceived it as a threat to the F-15 program.However, the Air Force's leadership understood that its budget would not allow it to purchase enough F-15 aircraft to satisfy all of its missions.