 While the B-29 was still considered useful in the post World War II inventory, the numerous problems with development, (i.e.including the freezing of the design in 1942) and the fear that the postwar US Congress would not fund the purchase of a design that still had significant quantity in storage, led to the radically redeveloped B-29D being redesignated the B-50A.While the B-50A looked similar to the B-29, Boeing had redeveloped the airframe with a new stronger alloy skin, redesigned main spar, taller vertical stabilizer, and improved engine cowlings.