The Messerschmitt Bf 109 was a German World War II fighter aircraft designed by Willy Messerschmitt in the early 1930s. It was one of the first true modern fighters of the era, including such features as an all-metal monocoque construction, a closed canopy, and retractable landing gear. The Bf 109 was produced in greater quantities than any other fighter aircraft in history, with a wartime production (September 1939 to May 1945) of 30,573 units. Fighter production totalled 47% of all German aircraft production, and the Bf 109 accounted for 57% of all fighter types produced. 2,193 Bf 109 A-E were built prewar, from 1936 to August 1939. An additional 1,000 or so were manufactured postwar under licence as Czechoslovakian built Avia S-99 & S-199s and Spanish Hispano Aviación HA-1109 and HA-1112 Buchons.