American Airlines announced Tuesday that it agreed to purchase aircraft that are still in development as it looks to expand its commercial fleet.

The company stated that it placed a non-refundable deposit for an initial order of 20 Boom Supersonic Overture aircraft, with an option to buy an additional 40.

“Looking to the future, supersonic travel will be an important part of our ability to deliver for our customers,” said Derek Kerr, American’s chief financial officer.

Boom recently revealed its final production design for the Overture, a high-speed aircraft the company claimed would be able to fly over water twice as fast as today’s commercial aircraft.

The Overture is slated to roll off the factory floor in 2025. It will have its first test flight in 2026. If all goes well, it will be passenger-ready in 2029, according to American Airlines.

The supersonic aircraft will supposedly fly at such a high speed that Boom claimed it would be able to travel from Miami to London in under five hours and Los Angeles to Honolulu in three.

Boom CEO Blake Scholl stated, “We believe Overture can help American deepen its competitive advantage on network [carriers], loyalty, and overall airline preference through the paradigm-changing benefits of cutting travel times in half.”

Other carriers signed on to the Overture’s 130-deep order book include United Airlines and Japan Airlines.

American Airlines signaled optimism about the future with its new investment. Still, Allied Pilots Association, the union representing American Airlines pilots, criticized the announcement, calling it a ploy intended to grab headlines.

The union said it would prefer to see the airline correct its serious operational problems.

“It matters not what airplane you book … whether it travels at the speed of sound or it’s subsonic. A cancellation is a cancellation,” Dennis Tajer of the Allied Pilots Association told WFAA.

American Airlines has faced many challenges this year, including an industry-wide pilot and staffing shortage, frequent cancellations, and problems with flight schedules.

The airline announced it would suspend service in four cities this September, including Islip and Ithaca in New York, Dubuque, Iowa, and Toledo, Ohio, citing the pilot shortage.

In addition, it plans to cancel hundreds of flights out of Philadelphia in the coming months in an attempt to ease operational problems and improve reliability.

In total, more than 1,800 American domestic flights have been canceled through October.