FILE PHOTO: A U.S. Air Force F-16 Fighting Falcon aircraft takes off for a nighttime mission at Bagram Airfield, Afghanistan, August 22, 2017. REUTERS/Josh Smith
FILE PHOTO: A U.S. Air Force F-16 Fighting Falcon aircraft takes off for a nighttime mission at Bagram Airfield, Afghanistan, August 22, 2017. REUTERS/Josh Smith