F-16 Fighting Falcons Thunderbirds perform a five-ship formation after refueling from a 92nd Air Refueling Wing KC-135 Stratotanker on Sept. 1, 2014, over Glacier National Park, Mont. The Thunderbirds were making their way back to Nellis AFB, Nev., where they are assigned to the 57th Wing's U.S. Air Force Air Demonstration Squadron.