A major U.S. airline placed a multibillion dollar bet on the return of luxury and business travel Thursday, inking a deal for a fleet of supersonic jets 18 years after the Concorde airliner was discontinued.

United Airlines announced the purchase of 15 planes from Denver-based Boom Supersonic, with the option of purchasing an additional 35 aircraft. The deal comes as airlines, which saw passenger counts plummet amid the pandemic, have experienced a recent resurgence, with airport security screenings reaching their highest numbers in more than a year.

While other airlines have placed preorders for supersonic jets, United is the first to place an order with an upfront financial commitment, said Boom chief executive Blake Scholl. Under terms of the agreement, United said it will make the purchase when the company’s Overture aircraft meet the airline’s safety and sustainability requirements.

United did not disclose the financial terms, but Boom officials said the Overture aircraft is priced at $200 million, which would make the deal worth $3 billion.

“This is a historic moment,” Scholl said. “This is the first true order of supersonic planes since the 1970s. Supersonic is back in a big way.”

After 27 years of operation, the last commercial supersonic jet, the Concorde, stopped flying in 2003. While luxurious, by the end British Airways and Air France cited high costs and low demand for their demise.

The average ticket price was about $12,000 when the aircraft was discontinued. A fatal 2000 crash outside Paris that killed 113 people and new security concerns after the Sept. 11, 2001, terrorist attacks also were factors.

The promise of faster travel, particularly by supersonic jet, has long had appeal in the industry, even as making it affordable and environmentally friendly has proved elusive.

The Overture jet would be capable of flying at Mach speed 1.7 — about twice the speed of today’s fastest commercial jetliners. That would mean a flight between New York and London would take 3½ hours instead of the current 6½ hours, the company said. The jets would offer all business class seats for 65 to 88 passengers, with service beginning by 2029, Scholl said.

While it will be up to airlines to set ticket prices, Scholl said he envisions fares near $2,500. The planes also are expected to run on sustainable aviation fuel, making them “net-zero carbon from day one,” according to United’s announcement.

United said it is eyeing possible routes that include Newark to London, or San Francisco to Tokyo, which could be done in six hours compared with the current flight time of more than 10 hours. Federal Aviation Administration rules prohibit supersonic travel over land.

Peter McNally, global sector lead for industrials materials and energy at investment research firm Third Bridge Group, said United’s deal is not its “first futuristic travel investment” of the pandemic. In February, the airline announced an agreement with Archer to develop electric vertical takeoff and landing, which are battery-powered, short-haul aircraft that would operate in urban areas.

McNally said the agreement with Boom Supersonic might enable United to attract lucrative business travelers. According to a Third Bridge analysis, 70 percent of business travelers say they would pay a premium to fly business-class supersonic, he said.

United chief executive Scott Kirby said in a statement that the air carrier “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.”

The deal with United is a show of faith considering Boom’s plane has yet to be built or approved by regulators, a process that could take years.

Last month, Aerion Supersonic, a Boom competitor, announced it was ending operations, citing the difficulty of “the current financial environment.” The Nevada-based company had released details of its proposed AS3 supersonic airliner in March.

Scholl said Boom will begin test flights of a scaled-down version of the Overture, the XB-1, later this year or in early 2022.

He said much has changed since the Concorde began test flights in the late 1960s.

“Fifty years later, we have advanced computer optimized aerodynamics. We have new lightweight materials. We have vastly improved engines that are quieter and more efficient, and importantly, we also have sustainable aviation fuel,” Scholl said. “Put these all together and you can build a new generation of supersonic airplane that’s 75 percent less expensive to travel on than the Concorde.”

One of those planes, the Concorde 205, is on display at the Smithsonian Institution’s Steven F. Udvar-Hazy Center near Washington Dulles International Airport. It was donated to the museum by Air France.