Onlookers wave as the last Concorde passenger flight ever takes off from John F. Kennedy International Airport en route to London on October 24, 2003.
Photo: Mario Tama/Getty Images
Air travel is about to get a lot faster – or so the headlines say. “American Airlines will buy supersonic jets amid the hype for ultra-fast travel,” Washington declared. post on Wednesday morning. “World’s fastest supersonic jet ‘Overture’ to usher in new era of supersonic travel,” New York post announced. They were linked to American Airlines’ announcement that it had placed an order for 20 supersonic Overture jets from a start-up called Boom. The planes will carry up to 80 passengers at a speed of Mach 1.7. Better yet, they will burn a special fuel that will make them carbon neutral.
All this is very exciting, if it happens. But there’s plenty of reason to believe it won’t — not least because, for years, similar claims have repeatedly come up empty. “It’s just PR,” says aviation analyst Brian Foley. Supersonic airlift is, he says, “still a long way off,” adding, “It’s fun to dream.”
To hear Boom tell it, the project is moving along at a brisk pace, and later this year the company says it will break ground on a plant in North Carolina. “We will begin production in 2024, with the first Overtures rolling off the line in 2025,” says Boom President Kathy Savitt. Flight testing and certification will follow shortly. “We estimate that the first passengers will be able to fly an Overture by the end of 2029,” she says.
Boom has made similarly ambitious claims before. In 2016, the company said it would make three-hour transatlantic flights by 2023. Meanwhile, it hasn’t even flown a scale model. “It’s always a decade in the future,” Foley says.
The reality is that developing any new airframe is an extremely expensive and lengthy process that even aviation heavyweights approach with trepidation. The A350 took Airbus a decade and $15 billion to get from the drawing board to the runway. Add in the technical challenges of supersonic flight and you’re climbing an even higher mountain. Industry analyst Richard Aboulafia has speculated that a project like Boom could cost $20 billion to develop.
Aircraft designer and longtime industry watcher Peter Garrison says those hurdles put him in the skeptic camp, “just knowing how hard it is to pull off a project like this. As with all such ambitious projects, milestone dates continue to be pushed back and costs continue to rise.”
A big part of the challenge is developing an engine. Supersonic flight is technically challenging and requires a particularly strong and durable power plant. Because no other commercial supersonic airplanes exist, there is no off-the-shelf Boom engine that can simply hang under the wing. “It will be a specially modified engine for us,” Savitt admits.
Rolls-Royce, which has been in talks with Boom, told aerospace publication Air Current earlier this year that it would not pocket the development costs. “If Boeing or Airbus come out with a new product, the engine and avionics providers will pay for most of the development in anticipation of further revenue,” says Foley. “But this is more of a special program.”
Even if Boom could build and certify the Overture, its customers would need to be able to operate the aircraft profitably. Given the high fuel and maintenance costs of such an aircraft, seats would necessarily be a high-ticket item. A Concorde chair sells for about $20,000 in today’s dollars. Even if Savitt is correct in estimating that the Overture will be able to operate profitably at 75 percent of that rate or less, that’s still a lot of money for a minimal rate given that the plane will be allowed to fly supersonic only over the oceans, as the sonic boom would disturb anyone on land.
Finally, there is the claim that Overture will be carbon neutral. Boom says the plane will run on “sustainable aviation fuel,” or SAF, a catch-all term that includes biofuels and synthetic hydrocarbons captured from the atmosphere. But the simple fact is that once a manufacturer sells an airplane to an airline, it cannot say what kind of fuel it burns. SAF, says Foley, “is not abundant, it is not available everywhere, and it is extremely expensive. Given that the airlines are all cost conscious, this will be a real decision tree for them.”
The daunting challenges of building a supersonic transport have already doomed another start-up that was trying to do the same. Last year, Aerion Supersonic, a Boeing-backed venture, closed its doors after running out of money. Another, Spike Aerospace, has suspended efforts.
For his part, Garrison says his frustration at past failures of these projects is tempered by the knowledge that, even if they ultimately worked, they would not have benefited people like him in any way. “It’s just to make some rich people happier,” he says.