Chief of NGB swears in Guardsmen to begin Thunder air show
Senior Airman Lindsey Horton, a recruiting assistant in the Kentucky Air National Guard, takes the oath of enlistment during a mass swearing-in ceremony on the Clark Memorial Bridge in downtown Louisville, Ky., April 18, 2015. The ceremony, which kicked off the Thunder Over Louisville air show, was led by Army Gen. Frank J. Grass, chief of the National Guard Bureau. (U.S. Air National Guard photo by Maj. Dale Greer)