Uber held its second annual “flying taxi” conference in Los Angeles this week, so we have a bunch of cool new concept images of weird, drone-helicopter hybrids that you could use to fly across town sometime in the next decade. Or not! Who knows if this thing will get off the ground? But if it does, it will be because of these five companies.

Embraer and Pipistrel Aircraft, two aircraft manufacturers that are working with Uber, released new concept images of aircraft they plan on building for the ride-hailing company’s ambitious project. And California-based Karem, which is the latest aircraft manufacturer to partner with Uber, had a new vehicle to show off as well.

Who knows if this thing will get off the ground?

Electric flight is still in the very early stages of development, and it’s not clear whether the technology, regulatory, and infrastructure hurdles can be overcome in time to meet Uber’s schedule. That said, Uber has assembled an impressive lineup of aircraft equipment manufacturers to help realize its vision of urban air mobility.

In addition to Karem, Embraer, and Pipistrel, Uber is partnering with Boeing subsidiary Aurora Flight Sciences and Bell (formerly Bell Helicopters) to develop aircraft for the flying taxi project. (A previous partner Mooney is no longer working with Uber.)

Uber has said it is looking for partners that can meet its technology specifications — electric-powered, minimal noise, and vertical take-off and landing capabilities — as well as a company that can scale production to build tens of thousands of vehicles to meet the demand of Uber’s on-demand service.

Karem is smaller aircraft manufacturer, but it’s still an interesting choice for Uber. Abe Karem, founder and chairman of the company, is a pioneer in drone technology. He’s been called “the dronefather” and “the man who invented the Predator” drone (although he makes clear it wasn’t his idea to put missiles on it).

Uber released images of its own concept aircraft earlier today and had a tiny model version on display at the conference. But it's important to note that Uber does not plan on manufacturing any of the vehicles used for its aerial taxi service. Instead, it will lean on its manufacturing partners to design and build these electric vertical take-off and landing (eVTOL) aircraft, as well as scale production to meet the demands of the proposed urban air mobility service.

Embraer

Brazilian aircraft builder Embraer is over 48 years old, making it one of the more experienced manufacturers to join Uber’s project. The company has around 19,000 employees worldwide, an annual revenue of $5.8 billion, and produces commercial, military, and agricultural aircraft. Urban air taxis, though, and electric ones to boot, would be a new venture for the company.

“This is a great concept but is a big challenge, no question about that,” said Embraer CEO Paulo Cesar Silva.

Aurora Flight Sciences

Aurora Flight Sciences, which specializes in autonomous aviation systems, was purchased by Boeing last year. The company has flown over 30 unpiloted flights since its founding in 1989, including a military helicopter that can be piloted using just a tablet.

During the Uber conference, Aurora CEO John Langford lamented the fact that there have been five decades of aviation technology development that haven’t moved the needle for on-demand transportation or reversed the downward trend in pilot jobs. He said autonomy was the key to turning those numbers around.

Karem

Karem’s “Butterfly” concept is a quad tiltrotor with four large propellers mounted on the wings and tail. The vehicle has larger propellors than some of the other eVTOL prototypes, which helps create a lower demand on the vehicle’s battery, explained Ben Tigner, CEO of Karem Aircraft. The slow-turning rotors also produce less noise than normal, which could be a crucial factor in winning over NIMBY-minded urban residents.

Karem is working toward building a full-scale demonstrator of its Butterfly concept.

Bell

Bell Helicopter rebranded as just “Bell” last February, as it seeks to reimagine its identity as a vertical flight company. Nonetheless, the bulk of the companies revenues are in commercial and military helicopters and tilt-rotor aircraft.

Bell first showed off its air taxi cabin concept at CES this year. At Elevate, conference attendees lined up to try out Bell’s VR experience inside the vehicle prototype. The air taxi concept is similar in many ways to another aircraft revealed last year: the FCX-001. Looking like a helicopter from Metal Gear Solid, the concept vehicle was meant to serve as a platform for some of Bell’s ideas about the future of vertical flight.

Pipistrel Aircraft

Pipistrel Aircraft, based in Slovenia, also used the occasion of the Uber event to rebrand itself as “Pipistrel Vertical Solutions.” The company already produces tiny, electric-powered aircraft that can be purchased today.

Its latest concept looks straight out of Star Wars and lacks many of the features — tiltrotors, visible propellors — that the other prototypes have. Pipistrel director of R&D Tine Tomazic said the aircraft will be able to go longer distances at higher speeds than previous models. And it will be part of a “family of eVTOL” that includes three other concept aircraft, Tomazic added.