 Complete the following phrase:  In May 1972 the group was activated in the reserves as the 507th Tactical Fighter Group, flying Republic F-105 Thunderchiefs, and replacing the 937th Military Airlift Group at Tinker. It was the first reserve group to participate in a Red Flag exercise or to deploy to Turkey for its annual tour of active duty. Upgrading to McDonnell F-4 Phantom IIs in 1980 and to General Dynamics F-16 Fighting Falcons in 1988, the group flew fighters until 1994. As the 507th Air Refueling Group, it began the worldwide air refueling mission with the Boeing KC-135R Stratotanker. From 1996 to 1997 it was assigned the 513th Air Control Group flying the Boeing E-3 Sentry AWACS aircraft and from 2008 to 2015 the 137th Air Refueling Wing of the Oklahoma Air National Guard was an associate unit of the wing. The wing participated in Operations Enduring Freedom and 