RAF the full name of the British air force. Armed service charged with the air defense of Britain and other international defense obligations. It originated in 1911, when an air battalion of the Royal Engineers was formed with one balloon and one airplane company. The air battalion was assumed into the Royal Flying Corps (RFC) in 1912, and in 1918 the RFC and Royal Naval Air Services were merged into the RAF. (The Fleet Air Arm was returned to the Royal Navy in 1937.) The Royal Air Force College was established at Cranwell, Lincolnshire, in 1920 and the RAF Staff College at Andover, Hampshire, in 1922. During World War II, pilots of the RAF Fighter Command distinguished themselves in the Battle of Britain, and Bomber Command conducted massive bombing raids on the German homeland. All front-line units are now combined under the RAF Strike Command; Personnel and Training Command handles recruiting, training, pensions, and other personnel issues. Uniformed RAF personnel numbered some 48,000 at the start of the 21st century