Conceived as the solution to provide fighter escort protection for heavy bombers, the XF-85 was the first and only aircraft designed as a parasite fighter to be launched by a trapeze mechanism from the bomb bay of the Convair B-36 and Northrop's planned B-35 flying wing. McDonnell built two prototypes in 1947 which were tested under a B-29, but great difficulties were encountered in attempting to dock the Goblin back to the mothership, requiring a very skilled pilot. With improvements to air-to-air refuelling, docking problems and superior Soviet opposition, the program was abandoned in 1949

The XF-85 Goblin was designed to be carried by the Northrop B-35 and Convair B-36 bombers for defense against interceptors, much like the Curtiss F9C Sparowhawk did with the US Navy Airships Akron and Macon in 1929. Performance of the jet was marginal and the trapeze set up was difficult to use so only two aircraft were built and the project was cancelled in 1949.