On Aug. 14, 1941, the U.S. Army Air Forces placed its first order with the tiny McDonnell Aircraft Corp. for two prototypes of a novel, twin-engine, long-range fighter with a pressurized cabin.

The XP-67 was completed in St. Louis, Mo. in December 1943, but the temperamental engines caused the airplane's first flight to last only six minutes.

During a Sept. 6, 1944, test flight at Lambert Field in St. Louis, the right engine burst into flames. The XP-67 landed safely, but the prototype was lost. McDonnell wanted the Army Air Corps to provide the money to replace the engines with a different kind. Instead, the program was canceled and the second prototype not completed.