Matthew Barzun, U.S. Ambassador to the United Kingdom of Great Britain and Northern Ireland, left, speaks with U.S. Air Force Col. Angela Cadwell, 501st Combat Support Wing commander, right, and Air Force Col. Douglas Mellars, 422nd Air Base Group commander, center, before a visit by President Barack Obama to RAF Fairford, United Kingdom, Sept. 3, 2014. Cadwell, Mellars and Barzun were on hand to greet the president before he travelled to Wales for the 2014 NATO Summit. (U.S. Air Force photo by Staff Sgt. Jarad A. Denton/Released)