Late in the war, several air-launched piloted V-1s, known as , were built, but these were never used in combat. Hanna Reitsch made some flights in the modified V-1 Fieseler when she was asked to find out why test pilots were unable to land it and had died as a result. She discovered, after simulated landing attempts at high altitude, where there was air space to recover, that the craft had an extremely high stall speed, and the previous pilots with little high-speed experience had attempted their approaches much too slowly. Her recommendation of much higher landing speeds was then introduced in training new volunteer pilots. The s were air-launched rather than fired from a catapult ramp, as erroneously portrayed in the film "Operation Crossbow".