The QF-4 Phantom flew its final unmanned mission this month while serving as an aerial target during F-35 Lightning II testing, the U.S. Air Force said.

The final flight took place above the White Sands Missile Range on Aug. 17, the service said in a statement.

The QF-4 has served as a target for a variety of next-generation weapons over the past 15 years.

The QF-4 program is slated to end later this year, as such services will be performed by QF-16 aircraft, a modified version of the F-16.

The Phantom will still be used in manned flights through December.

The QF-4 fleet's age and limited capabilities have led to its increased obsolescence, the service said.

The QF-16 begins the next chapter in advanced aerial targets, supporting more technologically superior air-to-air weapons testing and evaluation programs.

The F-4 Phantom served in Vietnam and as recently as the Gulf War.