Archer Aviation received a $10 million predelivery payment from United Airlines for 100 electric flying taxis, the startup said Wednesday. The move is the latest in a series of steps by commercial airlines to invest in the new hybrid aviation technology.

California-based Archer Aviation is one of several companies seeking to produce and authorize electric vertical takeoff and landing aircraft for commercial flights. eVTOLs are hybrids that take off and land like a helicopter and are designed to be used for short-distance travel across cities.

As a new technology, eVTOLs like those developed by Archer need approval from federal regulators to begin commercial service and allow companies like United to formally purchase aircraft. In a press release, Archer said it recently completed its preliminary design review process and is now advancing to the next development phase. The US Federal Aviation Administration has said recent regulatory shifts to the certification process for eVTOLs shouldn't prevent companies from gaining certification by the end of 2024.

United previously announced plans to buy up to 200 flying taxis from Archer, a deal worth $1 billion. United isn't the only commercial airline to invest in eVTOL travel. Last year, American Airlines said it had plans to invest $25 million in Vertical Aerospace Group, a UK-based eVTOL startup. 

Michael Leskinen, president of United Airlines Ventures, spoke about the predelivery payment in a statement, emphasizing the potential for eVTOLs to bring convenience to customers while reducing carbon emissions for the company.

"We believe eVTOLs have the potential to both help achieve carbon-neutral travel and serve as an innovative new tool to change how United customers experience comfort, convenience and efficiency during their commutes within cities across the globe," he said.

The announcement was reported earlier by The Wall Street Journal.