the Cherbourg Peninsula. For the remainder of the month it was engaged in air interdiction, striking airfields, rail systems and roads and depots behind enemy lines. The group was also diverted to tactical targets for shorter periods. In July 1944, it supported Operation Cobra the breakout of ground forces at Saint Lo. During Operation Market Garden, the attempt to secure bridgeheads across the Rhine River in the Netherlands, it supported the British 1st Airborne Division. It provided similar support during the Battle of the Bulge in December 1944 and January 1945, and Operation Varsity, the airborne assault across the Rhine in March 1945. The group flew its last combat mission on 20 April 1945. In fourteen months in combat, the group had flown 7086 sorties. It claimed the destruction of 33 enemy aircraft, but lost 83 Flying Fortresses. Following V-E Day, it transported prisoners of war from Austria to France. The air echelon departed Glatton between 19 and 23 May, while the ground echelon sailed on the on 24 June, arriving at the New York Port of Emarkation five days later. It assembled at Sioux Falls Army Air Field, South Dakota in late July. It was inactivated there the following month. Empire State Building accident On Saturday, 28 July 1945, Lieutenant Colonel William F. Smith lost his way while ferrying a 457th North American B-25 Mitchell bomber from Bedford Army Air Base to Sioux Falls via Newark Airport. Emerging from low cloud at about Smith found himself among the skyscrapers of Midtown Manhattan. His aircraft crashed headlong into the 79th floor level of the Empire State Building, killing Smith, two passengers and eleven office workers. The B-25 exploded on impact spraying burning fuel into 34th Street below, one of the engines completely passing through the building and out the other side. Air refueling operations On 1 July 1993, Air Mobility Command (AMC) transferred its crew training mission at Altus Air Force Base, Oklahoma to Air Education and Training Command (AETC). Although the 97th Air Mobility Wing remained the host at Altus, it became an AETC wing. The two operational air refueling squadrons at Altus, the 11th and 306th Air Refueling Squadrons, and their Boeing KC-135R Stratotankers were transferred to the reactivated 457th Operations Group. The 457th's squadrons deployed personnel and aircraft to Aviano Air Base, Italy, and Incirlik Air Base, Turkey to support Operation Northern and Operation Southern Watch duties