USAF XB-70 Contractor Model. Approx. 16 in. long. Made by Topping, Inc. of Akron, Ohio for North American Aviation, Inc. The XB-70 was an experimental supersonic bomber designed for the United States Air Force (USAF). After the first flight of the prototype in 1964, a political decision resulted in only two being built for aerodynamic research and not strategic bombing.