U.S. Army Staff Sgt. Gene Knight performs pre flight maintenance on an U.S. Army UH60 Blackhawk helicopter during the Patriot exercise at Volk Fields, Wis., July 14, 2008. Patriot is an annual exercise held across the United States that increases the warfighting capabilities of the National Guard and the reserve and active components of the United States Air Force and Army. The participation of Canadian, United Kingdom and Dutch forces increases combined effectiveness. (U.S. Air Force photo by Senior Airman Matthew Smith/Released)