Trenchard, Hugh Montague Trenchard, 1st Viscount, 1873-1956, British air marshal. He entered the army in 1893 and served in the South African War. During World War I he commanded the Royal Flying Corps. As chief of air staff (1918, 1919-29), Trenchard shaped the offensive air strategy (to the neglect of air defense) that the Royal Air Force adhered to into World War II. He was (1931-35) commissioner of the London police force and was created a peer in 1936.