U.S. Army Soldiers board a Korean Air Boeing 777 aircraft during the Mutual Airlift Support Agreement (MASA) exercise at Osan Air Base, Republic of Korea May 4, 2018. More than 500 Soldiers boarded the plane as part of the MASA to test interoperability and procedures between the United States military, ROK Air Force and Korean Air Lines. (U.S. Air Force photo by Tech. Sgt. Ashley Tyler)