The Navy has finished upgrading the Aegis Weapon System for two destroyers that give the ships the capability of carrying out in-theater air fighting as well as taking out ballistic missiles, the Navy said Monday. The Navy said the milestones were completed on the Arleigh Burke-class (DDG-51) destroyers, the USS Barry (DDG-52) and USS Benfold (DDG-65). Both vessels are expected to return to the fleet early next year, Naval Sea Systems Command said. A key centerpiece of the modernization, called…