The Royal Air Force is conducting “routine high-altitude training in the area,” said David Reid, director of aviation at the Eagle County Regional Airport. An C-17 Globemaster III passes over the Eagle County Fairgrounds and I-70 while practicing touch-and-go maneuvers at the Eagle County Regional Airport. Ben Roof / Special to the Vail DailyThe Eagle County area is renowned for its high-altitude training opportunities, with the U.S. Department of Defense’s only high-altitude aviation training site located at the Eagle County Regional Airport. The Royal Air Force is the aerial and space branch of the United Kingdom’s armed forces, and is a longtime ally of the U.S. military going back to World War II. The Royal Air Force conducted training missions above Eagle County last summer as well.