The black-and-white aircraft shown by Mr. Wiegand is less “Jetsons”-like flying car than a glider, with a carbon fiber body and 36-foot wingspan. Like several other flying taxis in development, it is battery powered, providing a range of 186 miles and a top speed of nearly 190 miles per hour. Inside the oval cabin will eventually be plush seats and other comforts for four passengers and a pilot.

The engines are packed inside four wings with flaps that rotate so the aircraft can take off and land vertically like a helicopter. But it is quieter than a helicopter, so it could potentially land in some areas traditionally off limits to aircraft.

The costs of the jets may eventually fall to several hundred thousand dollars each, Mr. Wiegand said. And with lower maintenance costs because there are fewer mechanical components, rides should cost roughly the same as an Uber or a taxi ride. Insurance companies have told him that they will provide him with risk coverage.

If successful, he said, the jets will transform urban transportation, with customers using Lilium’s app to book a flight from a network of small airports that connect suburbs, college towns and other hubs to cities. Imagine, he said, jets connecting areas across California or southern Germany that don’t have high-speed train lines.

Eric Allison, the head of Uber’s flying taxi effort, said the technolog ical hurdles were less complex than for autonomous vehicles ; there is less traffic in the air, and the first generations of the aircraft will have pilots.

Still, Mr. Allison said, no company has received government certification to fly commercially.

“That’s a tall order,” he said.