American Airlines has placed nonrefundable deposits on 20 Boom Supersonic's Overture aircraft and has agreed to options for as many as 40 more.
"Looking to the future, supersonic travel will be an important part of our ability to deliver for our customers," American Airlines CFO Derek Kerr said in a prepared remark. "We are excited about how Boom will shape the future of travel both for our company and our customers."
Boom says Overture will carry 65 to 80 passengers, traveling at Mach 1.7 (1,300 mph) with a range of 4,900 miles. The start-up manufacturer says it expects to complete production of the first aircraft by 2025, with the first passenger service on Overture planes to commence in 2029.
At a speed of Mach 1.7 over water, Overture could fly between American's Miami hub and its European base in London in five hours, compared to typical flight times of close to nine hours.
The companies did not reveal the amount of American's deposit. But with Wednesday's announcement, Boom has an order book of 130 Overture aircraft. Japan Airlines ordered 20 aircraft in 2017, and last year United ordered 15 Overture planes, with an option for 35 more.
Boom recently began taxi testing on its supersonic XB-1 demonstrator aircraft, which is one-third to scale of the Overture, though with some major design differences, including the number of engines. The company says that XB-1 demonstrator flights, which were initially slated to begin last year, are on track to launch before the end of this year.
In July, Boom unveiled a refined design for the Overture, including the addition of a fourth engine. Under previous plans, the plane was to be powered by three engines.
Boom has not announced what company will design the Overture supersonic engines. Boom plans to build its planes in Greensboro, N.C.