A pair of P-51D Mustangs represent World War II era aviation in formation with a QF-4 Phantom from the Vietnam Era and a F-15 Eagle from the modern day in an United States Air Force Heritage Flight during the 2006 National Championship Air Races at Stead Field in Nevada. The Air Force Heritage Flight program began in 1997 to commemorate the Air Force's 50th anniversary and has continued to combine aircraft from World War II, Korea, Vietnam, and state of the art fighters in formation flight displays. Photographed 09/06.