MCCONNELL AIR FORCE BASE, Kan. -- A KC-135 Stratotanker descends before landing at McConnell Air Force Base, Kansas, Jan. 18, 2018. Air Mobility Command’s tanker fleet, which is primarily made up of KC-135s, offloaded 1.177 billion pounds of fuel to U.S. and allied aircraft in 2017. (U.S. Air Force photo by Airman 1st Class Erin McClellan)