Lilium has successfully tested a two-seater aircraft. Now it wants to build a five-seater.

The mini jet is designed to fly at speeds of 187mph for one hour on a single charge.

Lilium has now been backed with over $100 million (£77 million) from big name investors including Skype's billionaire cofounder.

Lilium, a German aviation startup developing an electric car-sized aircraft, has been backed by investors with $90 million (£70 million).

Founded by four entrepreneurs in 2015, Lilium is a Munich-based startup with a patented mini aircraft that can take off and land vertically (like a helicopter), but also fly like a plane once airborne.

The series B funding comes from billionaire Skype cofounder Niklas Zennström, Chinese tech giant Tencent, and Obvious Ventures, whose cofounder Ev Williams is Twitter's cofounder and former CEO. Total investment in the company now stands at over $100 million (£77 million).

Ultimately, Lilium hopes that its aircraft — capable of flying at speeds of 187mph for around an hour on a single charge — will be used to ferry people around in a similar fashion to the way that taxis do today. The planes could hop across cities and land at designated rooftop terminals.

A computer generated image of a Lilium terminal. Lilium A render imagining Lilium jets on a rooftop. Lilium

Prices are yet to be determined, but there's an app in development that could be used to hail one of the company's mini-planes.

"It's difficult to say whether it'll be cheaper than an airline," Lilium COO Remo Gerber told Business Insider, adding that new routes such as St Albans to Birmingham would be possible. "We think a fare in a taxi or below is possible based on a people sharing a jet."

Lilium's engineers have successfully built and tested a two-seater prototype jet, but now they want to scale up to a five-seater jet with a one-hour battery life that will be no louder than a standard motorbike.

"They've proven that it's possible as a concept to go from a hovering flight to forward flight," Gerbers said. "And that's really the important thing as it goes from being a drone to an aircraft."

An app could be used to hail a Lilium jet., Lilium

Remo Gerber, who used to work for taxi hailing app Gett, declined to disclose the target date for the prototype of the five-seater plane. However, he did say that it'll be several years before Lilium can commercialise one of its jets though — citing certification as one of the lengthy hurdles that the company will have to navigate.

Google's Larry Page has invested in a flying car startup

Lilium isn't the only company working on a new generation of small flying vehicles. Google cofounder Larry Page has backed a startup called Kitty Hawk.

The COO refused to comment specifically on how Kitty Hawk was different to Lilium, but he pointed out that others working on similar projects don't have the same vertical take off and landing technology and they don't fly like planes once they're in the air.

"They're not going into forwards transition," he said, adding that they'll be based on lift from the rotors which will mean lower speeds, ranges, and battery life.

Some competitors are also developing autonomous aircraft but Gerber said Lilium's planes will have a pilot, at least to begin with.

Zennström, CEO and founding partner at Atomico, said in a statement: "Lilium has already demonstrated its leadership in this new eVTOL [electric vehicle take off and landing] industry and its once-in-a-generation transformative technology will have a seismic, positive impact on the world for generations to come.

"Now, with this latest investment round, Lilium has the capital and resources to speed ahead with the development of a commercially successful commuter aircraft that will transform the way we travel and help to solve some of the great challenges of our time."