However, it soon became apparent that the aircraft would not be ready in time for use in WWII. The Army decided to continue the B-35 program, but only in test status. The B-35B order was canceled and the YB-35 order was amended to include conversions to jet powered aircraft (YB-49 and YRB-49A). The development of the XB-35 continued but at a slower pace and the first flight of the XB-35 (S/N 42-13603) wasn't made until 25 June 1946.

The XB-35 was powered by four Pratt & Whitney R-4360 turbo supercharged radial engines initially driving dual contra-rotating 3 blade propellers. Because of serious and continuing problems  the 3-blade propeller was replaced by a 4-blade type which slightly increased the overall performance of the aircraft. Both XB-35s were scrapped in August 1949.