There were pilots aboard the aircraft which took to the skies over the Diablo Mountain Range in San Jose, California.

But all manoeuvres were carried out autonomously, with the JUH-60A Black Hawk navigating its way through a 23-mile course of hills and valleys.

Dubbed the RASCAL – Rotorcraft Aircrew Systems Concept Airborne Laboratory – the aircraft was equipped with a range of technologies, including computers and sensors, for it to operate on its own.