“Flying taxis” have long been the stuff of science fiction, but could the dream of flying over traffic be inching closer to reality? A growing number of companies think so—and think it can happen with few or no new emissions. 

Research for vertical take off and landing (VTOL) aircraft (meaning aircraft that can land without horizontally descending) dates back to the post-WWII era, when researchers worked to develop jets like the Harrier. But it’s gotten private sector interest in the last decade particularly, and some companies seem bent on launching VTOL aircraft as a commercial transportation service. 

MarketWatch reports that United Airlines has placed a $1 billion order for VTOL-oriented Silicon Valley startup Archer Aviation. China-based company Ehang is testing and showcasing its own self-flying passenger drone. Boeing is researching an electric version of the concept (eVTOL) in northern Virginia.  Early last year, Hyundai displayed a prototype of a VTOL developed with Uber, which has long been interested in the potential of air taxis. 

“Just as skyscrapers allowed cities to use limited land more efficiently, urban air transportation will use three-dimensional airspace to alleviate transportation congestion on the ground,” proclaims the rideshare company. 

Google’s co-founder has financed research into airborne cars. And there are about 300 other companies competing in this market, according to Fortune Magazine. 

But United’s investment is perhaps the most significant development yet, representing interest in VTOL by a major mainstream aviation brand. If testing goes well, the airline plans to acquire and deploy a fleet of 200 Archer aircraft. Additionally, a European consortium intends to launch VTOL flights in Florida. 

Archer is confident that its electrically-powered jets can be rolled out soon. Co-founder Brett Adcock tells Yahoo Finance that the company has had weekly test flights, and plans to deploy to the consumer market in 2-3 years. 

“We’re not taking any large technology bets,” Adcock says, emphasizing the use of existing technology. “In this decade, we will largely be replacing helicopters,” he asserts, because they plan to cut costs by automating the aircraft. Archer expects a cost of $3 per passenger mile. 

In France, a firm called Ascendance plans to deploy its own aircraft in 4-5 years, CEO Jean-Christophe Lambert says in an interview, also noting that the firm has had talks with some commercial carriers. He likewise expects relatively low fares, as to make the service comparable to car taxis.  

On that note, Archer and Ascendance see 10-250 mile trips as the main use case. Both expect use in passenger and cargo applications, including deployment for medical services and sanitation, but also just for standard passenger trips. The chief commercial officer at Lilium, another air taxi company, told CNBC that their prospective service may soon be able to offer $70, 6-minute flights between Manhattan and JFK Airport.

The real issue here will be regulations. The Federal Aviation Administration strictly regulates small-scale commercial flight operations. A Mercatus Center analysis details how FAA regulators shut down companies which booked passengers on private aircraft. Given the strict policies that many cities initially imposed on ridesharing services like Uber and Lyft, VTOL taxis are sure to face scrutiny from state and local policymakers, too.

Their concerns will likely revolve around environmental, noise, and right-of-way issues. Battery power could assuage the environmental concerns; around 28% of carbon dioxide emissions are transportation-related, and commercial air emissions account for 12% in the U.S. Yet Ascendance, along with other companies, plans to use hybrid-electric power sources, which should improve their energy efficiency.

Noise is another concern. According to Lambert, Ascendance believes that it can reduce the noise of its VTOL to the equivalent of an urban street but cautions that work on facilities is a crucial and challenging issue.  “We target a four time reduction relative to a helicopter.” Lambert said, “That would be the equivalent of a very noisy street.” 

And right-of-way issues (where do flying taxis launch from, where do they land, and what space in the sky do they consume?) is probably the main issue. The American Planning Association, to its credit, recently published an article about how U.S. cities should at least be thinking about this. But Dubai is already designating air space for it, and expects to have commercial VTOL activity by 2022. 

If Adcock, Lambert and other companies and investors are right, flying taxis can come to America, too. The question becomes whether the government limits regulation to quality-of-life and safety issues, or stifles the nascent industry with surplus regulations and cronyism. That said, just as Uber became too big for cities to shut down, a cheap “air rideshare” market that lets consumers circumvent traffic congestion may also prove too popular to undermine.