Matthew Barzun, left, the U.S. ambassador to the United Kingdom of Great Britain and Northern Ireland, speaks with U.S. Air Force Col. Angela Cadwell, right, the commander of the 501st Combat Support Wing, and Col. Douglas Mellars, the commander of the 422nd Air Base Group, before President Barack Obama visits Sept. 3, 2014, at RAF Fairford, England. The president stopped at RAF Fairford before continuing to Wales for the 2014 NATO Summit.