Two U.S. Air Force F-16 Fighting Falcons assigned to the 555th Fighter Squadron, Aviano Air Base, Italy, taxi on the runway during NATO’s enhanced Air Policing Allied mission at Graf Ignatievo Air Base, Bulgaria, Sept. 28, 2020. Airmen practiced responding to a quick reaction alert which built and maintained unit mission readiness and promoted interoperability with allies and partners. The presence of U.S. fighter aircraft in Bulgaria demonstrates NATO nations working together, maintaining and developing effectiveness at all levels. (U.S. Air Force photo by Airman 1st Class Ericka A. Woolever)