Looking Up Air Force Capt. Charles Kirchner, a D.C. National Guardsman, performs preflight checks on an F-16 Falcon fighter jet before takeoff during Green Flag at Nellis Air Force Base, Nev., April 15, 2021. The exercise provides combat training to joint and coalition warfighters. SHARE IMAGE: Download Image: Full Size (1.93 MB) Tags: Air Force Photo By: Air Force Airman 1st Class Zachary Rufus VIRIN: 210415-F-LY743-1002M.JPG Photo Gallery