Air Force scientists have announced that they had tested a robot kit that can turn virtually any plane into a self-piloting drone, through a program called ROBOpilot.

Why is that important? For starters, planes and drones are expensive. The drone shot down over Iran last month cost $220 million. For years the military has rushed to fund fabulous, exquisite drones of all shapes and sizes. Some, like the $15 million MQ-9 Reaper from General Atomics, are cheaper than manned military aircraft. But the big ones are more expensive than many types of civilian sport aircraft.

“Imagine being able to rapidly and affordably convert a general aviation aircraft, like a Cessna or Piper, into an unmanned aerial vehicle, having it fly a mission autonomously, and then returning it back to its original manned configuration,” said Dr. Alok Das, senior scientist with the Air Force Research Lab’s, or AFRL’s, Center for Rapid Innovation, in a statement. “All of this is achieved without making permanent modifications to the aircraft.” AFRL has partnered with DZYNE Technologies to produce the kit.

The system interacts with flight controls just like a human pilot, pushing all the correct buttons, flipping the switches, manipulating the yoke and throttle and watching the gages. “At the same time, the system uses sensors, like GPS and an Inertial Measurement Unit [essentially a way for a machine to locate itself in space without GPS] for situational awareness and information gathering. A computer analyzes these details to make decisions on how to best control the flight,” AFRL said in a statement. Once the flight is done, the kit can be pulled out and the plane reconverted to one requiring a human pilot.

On August 9, the system completed a two-hour test flight at Utah’s Dugway Proving Ground.

In theory, the same or a similar technology could be applied to expensive fighter aircraft. And the military has said that the next, sixth-generation fighter will be optionally manned. But the military has expressed reservations about allowing autonomous software to undertake lethal actions, so don’t expect to see ROBOpilot doing combat missions anytime soon.