Aircraft makers—from multinational giants to garage startups—offer a crazy variety of visions for air taxis that Uber might use.

The early days of flight saw a huge variety of designs—featuring oddities like planes with what we now call the “tail” in the front of the vehicle. After a few decades, the industry settled on the standard forms we recognize today based on cost and efficiency. But today electric technologies have made it possible to widen the space of what’s possible in terms of style, design, and material. “We’re at the same exciting period where we’re like, ‘Well, what is this supposed to look like?’” says Mark Moore, director of engineering, vehicle systems for the Uber Elevate air taxi program. “And no one, including myself, really knows the answer.”

So Uber is practically crowdsourcing the process, inviting aircraft makers to propose designs that meet Uber’s basic requirements: The planes must be capable of helicopter-style vertical take-off and landing (VTOL) and then transition to an airplane configuration, because it’s more energy efficient. Wings also let the craft travel faster, and Uber requires a speed of 150 miles per hour. They must be 100 percent electric, with enough juice to travel at least 60 miles. They have to be relatively quiet: about 15 decibels quieter than today’s screaming helicopters. And they should fit five people—four passengers and, until autonomous tech is ready, a pilot.

That leaves a lot of room for interpretation. Uber is helping out by proposing electric common reference models (eCRMs)—designs that aircraft makers can use as a starting point. Uber debuted its latest eCRM at its Elevate conference in L.A. this week. And several partners, from aeronautics giant Embraer to plucky small company Pipistrel, introduced their own take on Uber’s requirements. Some closely resemble Uber’s suggestions. Others are wildly different. (Pipistrel’s looks like something out of a Marvel movie.) Here are the latest concepts, some shown as sketches, others as scale models that were on display.


Uber eCRM 003

Uber’s latest common reference model (shown here in a scale mock-up) uses four helicopter-style rotors, mounted in pods that hold the batteries. When it reaches altitude of 1,000 to 2,000 feet, a top-mounted, rear propeller pulls the plane forward and the rotors retract into the pods to streamline airflow.


Embraer Concept

Embraer’s as yet unnamed concept craft bears some resemblance to Uber’s reference, though with much sleeker lines. The design—both inside and out—was based on ideas solicited online and from interviews with regular people who were asked to suggest what it should look like.


Pipistrel Concept

Looking suitable for The Avengers or Black Panther, Pipistrel’s concept has a hidden lift mechanism, possibly ducted fans, to raise it to altitude. It appears that a rear-mounted propeller pushes it forward. The company just teased this one image without explaining much of how it works. Company founder Ivo Boscarol promises simply that the plane is “screamingly fast.”


Karem Butterfly

Uber’s newly announced official aircraft manufacturer partner, Karem Aircraft has a long history in building VTOLs—which shows in this design. While it looks pretty conservative, the Butterfly claims some incredible performance. Even with today’s meager battery capacities (which isn’t enough for most planes to meet Uber’s requirement), it can travel a whopping 85 miles, according to simulations by Karem and Uber. With nine-minute recharges, the plane can operate indefinitely.


CarterCopter Air Taxi

Looking like a plane and a helicopter had a baby, this model is more clever than it appears at first. The Carter Aerospace craft would take off like an old school helicopter with the large rotor. As the craft rises, the propellers on the wings gradually take over, getting it up to a speeds of 175mph, says the company. By that point, the top rotor is spinning very slowly and causing minimal drag, they claim.


Airspace X

This big, working model has already flown in limited tests, says Jon Rimanelli, founder of Airspace X. With tilting wings it can use the same rotors for ascent and descent (when pointing up) and for plane-style flight when they face forward. ASX isn’t the first company to try tilting wings. Airbus, for example, uses four of them on the full-size Vahana prototype it began flight-testing earlier this year.

Via Fastcompany VTO