William Gebhardt was a pilot in the 55th Fighter Group / 338th Fighter Squadron, which he was assigned to on 18 June 1944. On 10 July 1944, he was momentarily put on detached service to the 357th Fighter Group/364th Fighter Squadron at Leiston, Suffolk. Back with the 55th FG, he was credited with 1 Me109 destroyed in air combat over the Düsseldorf area, Germany on 19 September 1944 on an escort mission for 3rd Bomb Division bombers. On a practice mission on 1 November 1944, the tail of his Mustang, 44-13784, suddenly ripped off in a dive exercise. Gebhardt bailed out and landed in the North Sea not far off shore. Squadron mate 2nd Lt (later promoted to 1st Lt) Richard C. Herbst who was flying behind him that day, relates : “Luckily, he landed near a convoy which was passing by at the time. One of the escorting destroyers swung over and picked him out of the water. This accident happened in November and the water was plenty cold. As usual, the dinghy snapped free when his chute opened, and to make matters worse his Mae West failed to inflate. Consequently he had to swim to keep himself afloat. Geb later told us that with all his heavy flying clothes on, it was all he could do to keep his head above water.” Lt Gebhardt was picked up by a naval destroyer 4 miles South of Orford Ness on the Suffolk coast, about 50km East of their base at Wormingford. His Mustang sank to the bottom ot the sea. There is no Missing Air Crew report (MACR) about this incident.

Bill Gebhardt was transferred to the 70th Replacement Depot at Stone, Staffordshire on 24 December 1944.

He served in the USAF during the Korean War.