Many well-known fighter pilots of the "Wehrmacht"'s "Luftwaffe" joined the new post-war air force and underwent refresher training in the US before returning to West Germany to upgrade on the latest U.S.-supplied hardware. These included Erich Hartmann, Gerhard Barkhorn, Günther Rall and Johannes Steinhoff. Steinhoff became commander-in-chief of the "Luftwaffe", with Rall as his immediate successor. Another pilot of World War II, Josef Kammhuber, also made a significant career in the post-war "Luftwaffe", retiring in 1962 as "Inspekteur der Luftwaffe" (Chief Inspector of the Air Force).