Maj. Carl Miller, Train, Advise, Assist Command-Air (TAAC-Air) instructor pilot, goes through pre-flight checklists with his Afghan Air Force counterpart on a training mission at Hamid Karzai International Airport, Kabul, Afghanistan, Sept. 21, 2015. The TAAC-Air mission is to train, advise and assist the AAF to be a capable, professional and sustainable air force. (U.S. Air Force photo by Staff Sgt. Sandra Welch/released)