Futuristic electric flying taxis like those in the movie "Blade Runner" could offer a more sustainable — and much faster — way to travel long distances than traditional car journeys, academics at the University of Michigan said on Tuesday.

Several firms are working to develop car-size vertical takeoff and landing aircraft (VTOLs) that can lift passengers above congestion, cruise at over 100 miles per hour (160 kph) and land in small spaces within crowded urban centers.

The vehicles could slash greenhouse gas emissions in half for three people on a 100-km (62-mile) trip, said researchers, though much of the savings come by assuming passengers will be more willing to share their space than they are in cars.