U.S. Air Force airborne jumpers with the 820th Rapid Engineer Deployable Heavy Operational Repair Squadron Engineers perform buddy checks on each other before departing for a mission in support of exercise Red Flag 11-2 over the Nevada Test and Training Range at Nellis Air Force Base, Nev., on Feb. 4, 2011. Red Flag is a realistic combat training exercise involving the air forces of the United States and its allies.