ELLSWORTH AIR FORCE BASE, S.D. – Master Sgt. Eric Petersen, 28th Security Forces Squadron plans and programs manager, washes an F-111 Aardvark at the South Dakota Air and Space Museum, April 28. Currently, 18 squadrons have sponsored an aircraft at the museum. The sponsorship instills unit pride, camaraderie and shows visitors from around the world Air Force history, heritage and honor. (U.S. Air Force photo/Airman 1st Class Matthew Flynn)