KEFLAVIK, Iceland — Col. William Lewis, 48th Fighter Wing vice commander, is saluted by Airman 1st Class Joshua Tarango, 493rd Expeditionary Fighter Squadron crew chief, during an alert exercise with the 493rd EFS at Keflavik International Airport May 22, 2012. The squadron, made up of both U.S. Air Force and NATO personnel, is fulfilling an air policing mission that assists in assuring Icelandâs air sovereignty. While there, the squadron is on alert 24/7 and the F-15C can be airborne within 15 minutes. (U.S. Air Force photo by 2nd Lt. Lyndsey Horn)