Big X
On a cross-country fuel stop at Hagerstown, Maryland, with Wittman's design, the Buttercup, Fairchild engineers expressed an interest in the design and even entered into negotiations for possible production of the aircraft. With the onset of World War II, production plans were shelved, but Fairchild contacted Wittman and proposed that a four-seat version would be marketable. Wittman designed the four-place "Big X" soon afterward.