Part of the "American Advances in Aviation" pane issued on July 29, 2005, this 37-cent stamp honors the Republic P-47 Thunderbolt, a key aircraft of the Second World War. The P-47 was the heaviest single-engine fighter of the war, and its robust construction and powerful Pratt & Whitney R-2800 Double Wasp engine earned it a reputation for being able to absorb significant damage and still bring its pilot home. Initially conceived as a high-altitude interceptor, the Thunderbolt evolved into a formidable multi-role aircraft. It excelled as an escort for Allied bombers on missions over Europe and proved to be a devastatingly effective ground-attack platform, armed with eight .50-caliber machine guns, rockets, and bombs. More P-47s were produced than any other U.S. fighter plane. The stamp's dynamic artwork captures the rugged and powerful essence of the "Jug," a plane that was instrumental in the Allied victory and a symbol of American industrial might during the war.