Corrects last name of CEO from Goldman to Goldstein in paragraph 4-5

By Shivansh Tiwary and David Shepardson

FARNBOROUGH, England, July 20 (Reuters) - Archer Aviation ACHR.N and defense technology company Anduril unveiled a co-developed autonomous aircraft platform on Monday, as aerospace startups increasingly tap partnerships that can lower development costs and speed up commercialisation.

The platform, developed together under a 2024 deal, is designed for both commercial and military applications.

Anduril introduced the defense variant, called Thunder, on Monday at the Farnborough Airshow. It's a Group 5 autonomous attack rotorcraft intended to fly alongside current and next-generation crewed attack and assault aircraft.

Archer CEO Adam Goldstein told Reuters the company built a very specific aircraft rather than retrofit an existing aircraft.

"Andruil has done a very good job of identifying needs and then building ahead of those needs before programs ever get announced... They identified a need, and we built a very specific aircraft for that need," Goldstein said.

"When you want to look at a product that can have large-scale use on the defense side, they typically will need to be built and designed and catered towards that very specific customer and use case."

Archer, best known for developing electric air taxis, plans to unveil its commercial variant and announce the platform's first commercial customers later this week, the companies said.

Developers of electric vertical takeoff and landing aircraft have been looking to expand beyond urban air taxi services, once touted as a trillion-dollar market, as certification delays, infrastructure hurdles and steep capital requirements weigh on the sector.

The Thunder is aimed at "anyone who operates Apache, anyone who operates armed reconnaissance helicopters,” said Shane Arnott, Anduril Industries’ senior vice president of programs & engineering.

Air taxi companies are also increasingly turning to hybrid-electric propulsion to extend range and improve mission flexibility beyond short urban hops, hoping to tap broader markets and cut losses.

The Archer-Anduril platform uses a series hybrid-electric powertrain and tilt rotors designed to vary rotor speed across flight conditions, with capabilities to support missions including military strikes, cargo movement, remote logistics and other operations from austere locations, the companies said.

For Archer, the partnership offers a path into defense and heavier-duty commercial markets while the outlook for the air-taxi market looks cloudy.

The companies have completed multiple test flights using full-scale surrogate aircraft, a step toward validating key systems. Thunder's first flight is planned for 2027.