An EHang all-electric Vertical Takeoff performs an unmanned display flight.

This is an empty "drone taxi" taking a short flight over the South Korean capital Seoul.

It is part of government plans to have a traffic management system in place to support the aerial taxis, possibly as early as 2025.

Jang Young-ki, deputy director of South Korea's transport ministry drone division, said they would help solve congestion in cities like Seoul.

"There are three key things to overcome when looking at the challenges that lay ahead," he said. "First is the appropriate technology, second is sufficient government funds and lastly, building trust in the minds of people is needed for them to be able to use drones."