The Junkers J. I (manufacturer's designation J 4; not to be confused with the earlier pioneering J 1 all-metal monoplane of 1915-16) was a German J-class armored sesquiplane of World War I developed for low-level ground attack observation and Army cooperation. It is especially noteworthy as being the first all-metal aircraft to enter mass production; the aircraft's metal construction and heavy armour was an effective shield against battlefield's small arms fire.
Made by Junkers.