 Based on that aircraft, he built the Wittman Big X in 1945, and the popular Wittman Tailwind series of homebuilts.During World War II, his Wittman Flying Service was part of the Civilian Pilot Training Program, training pilots for the Army Air Corps.After the war, Wittman finished eighth in the 1946 Thompson Trophy race with a clipped-wing Bell P-63 Kingcobra fighter.