A new flight regime. David Pearl and Jon Adams report on the extant and planned optionally piloted aircraft that are being used for multi-mission applications

Autopilots have been commonplace in fixed-wing aircraft for a while, taking control and maneuvering the aircraft in a range of situations. For decades, though, helicopters have been defined by a simple truth: someone must be in the cockpit. Whether rescuing a stranded climber, evacuating a wounded soldier, or dropping water on a wildfire, the helicopter has always been a crewed machine.

But that assumption is now being challenged.