OVER ARGENTINA -- An E-3 Sentry airborne warning and control system aircraft breaks away from a Mississippi Air National Guard KC-135 Stratotanker during a presidential support mission here. The Sentry, from the 552nd Air Control Wing at Tinker Air Force Base, Okla., deployed to provide airborne surveillance for the Summit. (U.S. Air Force photo by 1st Lt. Corinna M. Jones)