 In 1992, the Marine Corps and Air Force agreed to jointly develop the Common Affordable Lightweight Fighter, also known as Advanced Short Takeoff and Vertical Landing (ASTOVL).CALF project was chosen after Paul Bevilaqua persuaded the Air Force that his team's concept (if stripped of its lift system) had potential as a complement to the F-22 Raptor.Thus, in a sense the F-35B begat the F-35A, not the other way around.