Development contracts have begun to convert old F-16s into drones (QF-16) as replacement for old QF-4s based on Vietnam era F-4s. These drones are used for target practice and radar decoys, for pilot training, SAM/radar testing and Airborne missile testing. The F-4 was never a very good aircraft and its poor handling and lack of engine production has caused the AirForce to look elsewhere. Initially, six F-16s will be converted, but the AirForce plans to aquire at least 220 over time.
http://www.defenseindustrydaily.com/...o-Hands-06228/
Another aspect is the possibility future combat may include sacrificial waves of unmanned drones as bombers. Recent war game analysis of a combat with China showed conversions of their old Migs could drain defensive systems. The ability to convert old F-16s, as well as F-15s, in the same manner is something the US has had at its disposal. There's also no shortage of these aircraft, as the 3rd-largest air force on Earth is America's boneyard.
