U.S. Navy F/A-18 Hornet strike fighters perform tight formation maneuvers during the Air Expo held on Naval Air Station Patuxent River, Md., Sept. 3, 2011. The F/A-18 pilots are assigned to the Navy flight demonstration squadron, called the Blue Angels. This is the first time the Blue Angels have performed with a 50-50 blend of biofuel and jet fuel. The air show is part of a year-long commemoration of the centennial anniversary of naval aviation.