Colombian Air Force Kfir fighter jet crew chiefs signal Kfir pilots prior to a flight during Red Flag 18-3 at Nellis Air Force Base, Nev., July 27, 2018. The Colombian Air Force is participating in Red Flag, the U.S. Air Force's premier air-to-air combat training exercise, for the second time. (U.S. Air Force photo by Staff Sgt. Angela Ruiz)