About 12,732 units of the B-17 Flying Fortress were produced between 1936 to 1945. It is ranked third in a list of most produced bomber planes of all time, beaten by the Consolidated B-24 Liberator and Junkers Ju 88.  During WW2, about 40 B-17s were captured and modified by the Luftwaffe to suit their specific needs. About a dozen of these downed planes were successfully put back into the air and were used by the Nazis against the Allies. Three downed B-17s were also repaired and restored to flying status by the Japanese.