The Lockheed P-38 Lightning was a World War II American fighter aircraft. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a single, central nacelle containing the pilot and armament. The aircraft was used in a number of different roles, including dive bombing, level bombing, ground strafing, photo reconnaissance missions, and extensively as a long-range escort fighter when equipped with droppable fuel tanks under its wings. The P-38 was used most extensively and successfully in the Pacific Theater of Operations and the China-Burma-India Theater of Operations, where it was flown by the American pilots with the highest number of aerial victories to this date. America's top aces Richard Bong earned 40 victories (in a Lightning he called Marge), and Thomas McGuire (in Pudgy) scored 38. In the South West Pacific theater, it was a primary fighter of United States Army Air Forces until the appearance of large numbers of P-51D Mustangs toward the end of the war.