Every time you hear a bell ring, does another flying taxi company get its wings? Well, not quite, but every time the New York Stock Exchange opening bell rings these days, another next-generation aviation startup seems to be getting its listing on the Big Board.

The latest is Archer, a Palo Alto–based company that is one of hundreds around the world working on newfangled electric-powered aircraft that can take off and land vertically. It announced today that it will secure a public listing through a reverse merger with Atlas Crest Investment Corp., a NYSE-listed special purpose acquisition company, or SPAC.

The merged company, which will trade under the ticker ACHR, is expected to have a value of $3.8 billion after the transaction completes.

Archer follows Blade Urban Air Mobility, which went public in December through a merger with SPAC Experience Investment Corp. Blade currently operates helicopter transport services but plans to invest in a range of new landing pads to service all the flying taxis that technologists think will soon be buzzing through our skies. Joby Aviation, the electric vertical takeoff and landing aircraft (eVTOL) producer that bought Uber’s former flying taxi business, has hired investment bankers to also explore a public listing through a SPAC, targeting a $5 billion valuation, according to a Reuters report. Lillium, a competing air taxi startup from Germany that is backed by some prominent venture capital firms, is also considering a SPAC deal, according to a report in an industry trade publication.

There have also been a host of startups from other parts of the electric transport sector that have gone public through reverse mergers with SPACs in the past year: These include electric-car makers Fisker, Nikola, Lordstown Motors, Canoo, XL Fleet Corp., battery startup Quantumscape, and Lidar makers Velodyne Lidar and Luminar Technologies.

Archer has lined up some big-name backers that are putting money into the new public company: United Airlines and Stellantis, which owns Fiat Chrysler, along with the venture arm of Exor, the Agnelli family’s holding company. (Archer announced a deal with Fiat Chrysler last month that will give the startup access to the car company’s supply chain, lowering the costs of key parts.) Others include Mubadala Capital, the Emirati sovereign wealth fund; Putnam Investments; and Federated Hermes Kaufmann Funds. Collectively, those investors are putting $600 million into the new company.

Then there’s billionaire financier Ken Moelis and Jet.com founder and former Walmart e-commerce executive Marc Lore, an early investor in Archer, who are investing $30 million in the public entity too.

To help generate some pizzazz around its public listing, Archer also announced that United Airlines has committed $1 billion to buy its new aircraft “subject to United’s business and operating requirements,” with an option for an additional $500 million.

“Part of how United will combat global warming is embracing emerging technologies that decarbonize air travel,” United CEO Scott Kirby said in a statement. “By working with Archer, United is showing the aviation industry that now is the time to embrace cleaner, more efficient modes of transportation.”

That sounds good. But most of the dozens of eVTOL aircraft on drawing boards around the world, and the few that have actually undergone flight testing so far, are too small—carrying fewer than 10 passengers—and limited in range to make a huge dent in the carbon footprint of the world’s major airlines. They are much more likely to compete with journeys that today are covered by helicopters, not to mention cars, buses, and trains.

In fact, as an example of how its partnership with Archer might help curb climate change, United didn’t provide a comparison with one of today’s existing commercial flights: Instead, it estimated that the flying taxi would reduce the carbon footprint of a journey between Hollywood and Los Angeles International Airport by 50% per passenger. That’s a journey that today is mostly handled by car. (And, of course, that’s assuming the car those people are riding in isn’t already a Tesla, or a Prius Hybrid for that matter.)

United, according to a press release from Archer, sees the small eVTOLs as a way to feed passengers to its main hub airports, something the company says could start to happen as soon as 2024.

That’s an ambitious timeline considering that right now Archer doesn’t even have a certified aircraft. The company has revealed only artists’ renderings of its futuristic-looking plane, which it says will be able to fly distances of up to 60 miles at 150 miles per hour. That’s shorter than the distances being touted by some other eVTOL contenders: Joby has said it wants its flying taxis to travel up to 150 miles, and Lillium says its electric jet-powered airplane will handle trips up to 186 miles. But some industry insiders say Archer’s range projections are more realistic, given current electric motor and battery technology.

There are by one count more than 300 eVTOL companies vying to be the next Boeing or Airbus. Heck, both Boeing and Airbus are investigating eVTOLs too. Which of these flying taxi brands will dominate tomorrow’s airspace is anyone’s guess at this point. What’s far more clear is why all the flying car companies are flocking to the public markets right now: It takes a lot of money to get a new airframe type designed, built, tested, certified, and mass-produced. Meanwhile, public markets for new technologies—and electric transport in particular—have never been hotter. So it’s not surprising to see the founders of these startups, and their venture capital backers, leaping at the opportunity to raise funds, and possibly offer an exit to early investors at sky-high valuations.

SPACs offer an especially attractive glide path to the public markets for flying taxi firms. One advantage of these blank-check investing vehicles is that they allow companies to secure a public listing without having to disclose all the potential pitfalls and risks in their business models prior to selling shares.

Investors just have to hope that stock charts of Archer and its fellow flying taxi companies don’t resemble the flight paths of the planes these companies are creating: That vertical takeoff looks great, but watch the landing.