Missouri Farewell Defense Secretary Dr. Mark T. Esper bids farewell to Air Force Col. Jeffrey Schreiner, 509th Bomb Wing commander, at Whiteman Air Force Base, Mo., July 22, 2020. SHARE: Download: Full Size (1.6 MB) Tags: defense secretary, esper Credit: Air Force Senior Airman Thomas Barley VIRIN: 200722-F-WU042-1007Y.JPG Photo Gallery