Bockscar, sometimes called Bock's Car, is the name of the United States Army Air Forces B-29 bomber that dropped a Fat Man nuclear weapon over the Japanese city of Nagasaki during World War II in the second – and last – nuclear attack in history.n 9 August 1945, Bockscar, piloted by the 393d Bombardment Squadron's commander, Major Charles W. Sweeney, dropped a Fat Man nuclear bomb with a blast yield equivalent to 21 kilotons of TNT over the city of Nagasaki. About 44% of the city was destroyed; 35,000 people were killed and 60,000 injured.