NELLIS AIR FORCE BASE, Nev. -- Thunderbird F-16s perform the diamond formation during the 2009 Aviation Nation Open House. The open house is an opportunity for the Las Vegas community to view aerial demonstrations and static displays of various aircraft from the military. The open house also acts as the final air show of the year for the U.S. Air Force Air Demonstration Team "Thunderbirds." (U.S. Air Force photo/Tech. Sgt. Michael R. Holzworth)