The U.S. Air Force recently flew a F-16 with another F-16 but the second jet was being flown by algorithms.
By U.S. Air Force photo by Master Sgt. J. Scott Wilcox (U.S. Air Force photo 130919-f-ZN655-35) [Public domain], via Wikimedia Commons
There was a pilot on board the “unmanned” F-16 as a backup but both jets were able to keep in formation without input from the surrogate pilot.
The challenge was to see whether a manned fighter aircraft can be teamed with an unmanned aircraft.