The Bell P-39 Airacobra was one of the principal American fighter aircraft in service when the United States entered World War II. The P-39 was used with great success by the Soviet Air Force, which scored the highest number of individual kills attributed to any U.S. fighter type. Other major users of the type included the Free French, the Royal Air Force, the United States Army Air Forces, and the Italian Co-Belligerent Air Force. (Source Wikipedia)