David Grady, a fourth grader at Davidson Day Elementary School, Davidson, N.C., reads a thank you letter he wrote as a school project to a room of 200 U.S. Air Force service members as part of celebration ceremony for the services 67th Birthday at the North Carolina Air National Guard Base, Charlotte Douglas Intl. Airport, Sept. 18, 2014. (U.S. Air National Guard photo by Staff Sgt. Julianne M. Showalter, 145th Public Affairs/Released)