HAPSMobile, a joint venture created by Japan’s SoftBank Corp. and California-based AeroVironment, is jumping into the race to provide global broadband access from above, alongside SpaceX, Amazon, OneWeb and Telesat.

Unlike those four companies, HAPSMobile plans to use high-flying, solar-powered planes rather than satellites to transmit signals wirelessly over a wide swath of the planet’s surface. In that respect, the concept has more in common with the aerial broadband concept that Facebook was pursuing until last year.

Like Facebook’s plan, HAPSMobile’s concept relies on high-altitude platform stations, or HAPS. The venture’s ultralight Hawk30 airplanes would fly above the clouds at an altitude of 13 miles (20 kilometers) for months at a time. Each aircraft would have a wingspan of roughly 260 feet (78 meters) and sport 10 electric-powered propellers. Average flight speed would be about 70 mph (110 kilometers per hour), HAPSMobile and SoftBank said in a news release.

The plan calls for signals to be sent in the same frequency ranges used for terrestrial mobile telecom, making for a “seamless handover” between ground-based and aerial networks. HAPSMobile says it’s entered into a technology licensing agreement with Facebook for their advanced communication system.

AeroVironment, which specializes in the development of unmanned aircraft systems for military and commercial applications, said it has assembled the first Hawk30 for testing. The ceiling value for HAPSMobile’s design development agreement with AeroVironment was recently raised by $39 million to reach a total of $126 million.

HAPSMobile is targeting 2023 for mass production of the Hawk30 planes and the launch of commercial service. In the meantime, the venture will be working with Alphabet’s Loon, which started out as a Google project and is deploying balloon-based platforms to provide wireless telecommunications services.

In an unusual arrangement, HAPSMobile says it has decided to invest $125 million in Loon, with the intention of using Loon’s balloon platforms and technology to build out a global broadband network. Loon has the right to invest the same amount in HAPSMobile sometime in the future, and will be able to use Hawk30 aircraft once they go into production.

Loon and HAPSMobile will work on a common gateway or ground station network that could be deployed globally and used by both companies to provide connectivity over their respective platforms. The two companies could also share network connectivity in the air.

Representatives of the two ventures said the linkup would further their shared vision of providing high-speed connectivity to billions of people around the world who are currently underserved.

“Through HAPS, we aim to eliminate the digital divide and provide people around the world with the innovative network services that they need,” Junichi Miyakawa, who is the president and CEO of HAPSMobile as well as representative director and chief technology officer at SoftBank Corp., said in a news release.

Loon CEO Alastair Westgarth hailed “the beginning of a long-term relationship based on a shared vision for expanding connectivity to those who need it.”

“We see joining forces as an opportunity to develop an entire industry, one which holds the promise to bring connectivity to parts of the world no one thought possible,” he said.

HAPSMobile and Loon aren’t the only ventures that have a vision of providing broadband access from above. Here are some of the other contestants in the race:

The list doesn’t stop there: Boeing, Facebook and Luxembourg-based LeoSat have laid out plans for space-based internet access as well. Even Lockheed Martin has mentioned the idea of having a “cloud in space.” And Aurora Flight Sciences, a Boeing subsidiary, is working on a high-flying, solar-powered plane called Odysseus that looks a lot like the Hawk30.

How many satellites, balloons and signal-beaming drone aircraft can the world handle? How many of these ventures will come to fruition? In the next five or 10 years, we may well find out.