A U.S. Air Force Airman, assigned to the 721st Aerial Port Squadron, marshals a C-17 Globemaster III aircraft transporting three COVID-19 patients from Afghanistan during the first-ever operational use of the Transport Isolation System at Ramstein Air Base, Germany, April 10, 2020. The TIS is an infectious disease containment unit designed to minimize contamination risk to aircrew and medical attendants, while allowing in-flight medical care for patients afflicted by a disease--in this case, COVID-19. (U.S. Air Force photo by Staff Sgt. Devin Nothstine)