“We have been in contact with the F.A.A. and we see the regulators as friends,” Mr. Thrun said in an interview. He agreed that concerns about vehicles flying over our heads were legitimate. “I believe that all of us have to work together to understand how new technologies will shape the future of society, ” he said.

Two years ago, Mr. Thrun recruited two other pioneers, Mr. Robertson and Todd Reichert, aerospace engineers from AeroVelo, a University of Toronto spinoff company that won a coveted prize for a human-powered helicopter and set the land speed record for a bicycle last year.

They are flying under a special Federal Aviation Administration category for ultralight aircraft that does not require a pilot’s license and is intended for recreational flying in uncongested areas. To add an extra margin of safety, the Kitty Hawk engineers are sticking to flying over open water. The company said the final commercial product would look different and be far quieter than the test model.

“We hope that this is more of an exciting concept than what most people have had in their minds about flying cars,” Mr. Robertson said. “This is not yet that product in terms of what we will say and what it can do, but I think it demonstrates a vision of the future.”

Kitty Hawk could face stiff competition, not just from about a half dozen start-ups, but from the giant Airbus, headquartered in Blagnac, France. The aerospace firm has announced two different vertical takeoff and landing, or VTOL, concepts and is reported to be planning an initial test flight before the end of the year.

At the Geneva International Motor Show last month, Airbus proposed an autonomous vehicle named Pop.Up that would operate on the ground and in the air. And this year, the government of Dubai, in partnership with a Chinese firm, EHang, said it planned to begin operating an autonomous flying taxi in July. Also, Uber is expected on Tuesday to detail its “vision for the future of Urban Air Mobility” at a conference in Dallas.

There is no shortage of skeptics happy to point out the roadblocks for these vehicles. There is already significant resistance to the idea of unmanned drones flying over urban areas, and flying cars could face substantial opposition, even if they can be quieted to automotive noise levels.