Lilium says its five-seater jets can travel up to 186 in one hour.

Flying cars have for years been limited to the world of fiction. Now there are plenty of companies hoping to make the sci-fi dream a reality.

One such firm is Lilium, a Munich-based start-up with big ambitions for the future of transportation: a five-seater electric air taxi, due to launch commercial flights in 2025.

The main goal Lilium is hoping to achieve, according to Chief Commercial Officer Remo Gerber, is making such a service an affordable one that people can use just like they would a ride-hailing app like Uber.

Around the time Lilium was established, its founders realized they didn't want to make a "luxury product" or "something we sell to rich individuals," but a "service that's affordable," Gerber told CNBC in an interview.

To get a better idea of just how much that would cost, the executive used the example of taking New Yorkers from Manhattan to JFK Airport within six minutes for about $70.

For reference, Uber plans to take passengers in its helicopter ride-sharing service from Manhattan to JFK for a roughly $200 flight that takes around eight minutes.

Lilium says its aircraft, which takes off and lands vertically, can travel 300 kilometers in an hour after a single charge. In the U.K. that means it would be able to take someone from London to Manchester — in other words, from the South to the North of England – in one journey.