Shortly before the barracks scene, Keith David fell off of a seven foot railing outside the building while the actors were between shots, breaking two ribs and cracking two vertebra. He when on to film the scene in great pain and then went to the hospital afterwards.
The DOD (Department Of Defense) would not let them film the opening scene in an Air Force hanger, so the shot was done in at the North Ridge, CA VA hospital, with CGI airplanes added in. The cafeteria and barracks scene was shot there too.
According to 'Larry the Cable Guy', while they were shooting the movie, he gained 17 pounds and later stated he was probably the only guy who could gain weight running around the desert in 130 degree weather.