by STEVE WEINTZ

Far-off visions of the future don’t have as many airborne cars like they used to. But flying military jeeps were once very real—if impractical and dangerous to their pilots.

From the 1940s to the 1960s, the British and American militaries experimented with such rotorcraft. The jeeps never left the prototype stage. But it seemed like a good idea, at the time.

In theory, a jeep capable of taking flight has advantages to both ground and air vehicles. It could zoom over obstacles, ambushes and improvised explosive devices, without the cost and complexity of a helicopter.

But getting a small truck to fly is a trick engineers have yet to master, despite decades of effort. That may be about to change.

The flying jeep dates back to World War II. The planned invasion of France—and the huge logistical hurdles of such an operation—preoccupied Allied military planners. How do you move vehicles across the rough seas of the English Channel?

You can certainly move them by ship. But the necessity of getting the vehicles into action—and quickly—fostered the first serious attempt at building a flying jeep.

In 1942, the British Airborne Forces Experimental Establishment green-lighted engineer Raoul Hafner’s idea of attaching a free-spinning rotor and a set of tail fins to a Willys jeep.

Known as the Rotabuggy, Hafner’s concept proposed a jeep towed behind a large, propeller-driven airplane. The tow plane provided the forward thrust, while the rotor provided the Rotabuggy’s lift.

A two-man crew controlled the jeep using glider instruments, and swiveled a big upside-down joystick to tilt the rotor.

This being a British invention, ground tests employed a supercharged Bentley as the tow vehicle. Later, a Whitley bomber pulled the jeep through the air during flight tests.

But the Rotabuggy’s crude controls and unstable aerodynamics were dangerously rough on its crew.

After one bouncy landing, the jeep raced out of control down the runway. When the vehicle stopped, the pilot staggered out and lied down in exhaustion.

The Rotabuggy never saw combat. The development of the Horsa and Hamilcar transport gliders—used to carry airborne infantry and small jeeps into battle—served the British military’s requirements instead.