United Airlines announced a new partnership with Boom Supersonic to add aircraft to its global fleet and support the carrier’s cooperative sustainability initiative.

The deal would see United purchase 15 of the Denver-based aerospace company’s Overture planes once they meet the airline’s safety, operating and sustainability requirements. The carrier also has an option to purchase an additional 35 aircraft.

Boom Supersonic’s Overture planes can reach Mach 1.7, which is twice the speed of today's fastest aircraft. With the new fleet, United can connect more than 500 destinations in nearly half the time, such as Newark to London in just three and a half hours.

“United continues on its trajectory to build a more innovative, sustainable airline and today's advancements in technology are making it more viable for that to include supersonic planes,” United CEO Scott Kirby said. “Boom's vision for the future of commercial aviation, combined with the industry's most robust route network in the world, will give business and leisure travelers access to a stellar flight experience.”

“Our mission has always been about connecting people and now working with Boom, we'll be able to do that on an even greater scale,” Kirby continued.

When launched, the Overture planes are expected to be the first large commercial aircraft to be net-zero carbon from day one, optimized to run on 100 percent sustainable aviation fuel. The fleet is expected to roll out in 2025, fly in 2026 and carry passengers by 2029.

The new planes will also be designed with in-seat entertainment screens, ample personal space, and contactless technology, all of which enforce United’s strategy to invest in innovative technologies to build a more sustainable future of air travel.

“The world's first purchase agreement for net-zero carbon supersonic aircraft marks a significant step toward our mission to create a more accessible world,” Boom Supersonic CEO Blake Scholl said. “United and Boom share a common purpose—to unite the world safely and sustainably. At speeds twice as fast, United passengers will experience all the advantages of life lived in person, from deeper, more productive business relationships to longer, more relaxing vacations to far-off destinations.”