In 1968, ADCOM began the phaseout of the F-101 and F-102 interceptors from active duty units, with both types mostly being transferred to the Air National Guard. The F-101 would remain in a limited role on active duty until 1982, serving in such roles as towed target carrier aircraft and simulated enemy radar contacts for Airborne Weapons Controller students training for duties aboard the E-3 Sentry AWACS. The F-102 would see service until the mid-1980s as the PQM-102 aerial target drone. The F-106 Delta Dart, considered by many the finest all-weather interceptor ever built, was the primary air defense interceptor aircraft for the US Air Force during the 1970s and early 1980s. It was also the last dedicated interceptor in U.S. Air Force service to date. It was gradually retired during the 1980s, though the QF-106 drone conversions of the aircraft were used until 1998 as aerial targets under the FSAT program.