Five years from now, it might take three hours and 15 minutes to fly from New York to London, or five and a half hours to get from San Francisco to Tokyo. That’s half the amount of time it currently takes.

Those are the promises being made by several companies working on supersonic air travel. But to others, this is just a pipe dream.

Mach speed explained
Image: NASA

Boom Technology, a Denver-based start-up, has its first test flight planned for next year, with plans to launch the first commercial departures in 2023.

Haven’t we been here before?

The original concorde
Image: REUTERS/Lee Besford

Supersonic travel isn’t new: the technology has existed for decades. Concorde flights took off from 1969 to 2003.

But while Concorde made money in its heyday, ultimately it was not commercially viable.

However, Boom says it can reduce the cost of supersonic flights by 75% because of advances in technology. Taking a flight on its 55-seat aeroplane will be no more expensive than a business class ticket, says the company.

A model of Boom's jet
Image: Boom Technology

The plane – the XB-1 – has an advanced aerodynamic design, and is made with lightweight materials that can withstand supersonic flight. It also benefits from a more efficient propulsion system. The Concorde relied on an afterburner, which increased thrust but used up a lot of fuel.

It can fly at Mach 2.2, or 1451 mph (2335 kmph): that’s 2.6 times faster than a normal passenger plane. The company says it will be quieter and more efficient than its predecessor, Concorde.

Boom has some big-name backers, including Virgin Group and Japan Airlines.

Image: Boom Technology

No more sonic boom

Another problem for Concorde was the amount of noise it made. A sonic boom happens when a plane flies faster than the speed of sound. People on the ground hear a thunder-like noise.

Illustration of NASA’s planned Low Boom Flight Demonstration aircraft
Image: NASA / Lockheed Martin

NASA, in partnership with aerospace company Lockheed Martin, is building a much quieter supersonic plane.

Its X-plane can fly at supersonic speeds but creates a soft “thump” instead of the disruptive sonic boom. It recently completed a successful test flight at NASA’s Armstrong Flight Research Center in California.

“We’re now one step closer to building an actual X-plane,” said David Richwine, manager for the preliminary design effort under NASA’s Commercial Supersonic Technology Project.

A rendering of the Aerion supersonic jet
Image: Aerion

Lockheed Martin is also involved in a project with Aerion and GE Aviation to develop what it calls the world’s first supersonic business jet, the Aerion AS2. The plane is light and immensely strong thanks to its carbon fibre construction, similar to that used for modern fighter aircraft.

At the Paris Air Show last year, Boeing CEO Dennis Muilenburg said that hypersonic (which is even faster than supersonic) technology is a really important investment area for the future.

“We see future innovations where we will be able to connect anywhere around the world in about two hours maybe a decade or or so out,” he said.

However, he also said that the business case hadn’t been resolved yet. In other words, it could still remain too expensive to get off the ground.

Will it work?

Boom faces an uphill struggle convincing a conservative industry that a plane with only 50 seats and with a high demand for fuel will work commercially in the long term.

Aviation analyst Bjorn Fehrm says that Boom's main challenge will be making the technology work. "The lack of suitable engines is a major culprit for all present supersonic transport projects," he argues. "The only high jet engines are military fighter engines, but these do not have the fuel economy nor the reliability required for civil transport operation."

Fehrm adds that a new supersonic jet is achievable, but only "at the cost of three times higher fuel consumption per seat and nautical mile."

But some airlines - like Japan Airlines - clearly think that Boom is onto something.

Richard Branson, the founder of The Virgin Group, recently told Bloomberg that: “The next big thing, hopefully in my lifetime, will be supersonic travel coming back and people travelling around the world in next to no time.” Virgin Galactic’s manufacturing team, The Spaceship Company, has partnered with Boom to help create the jets.

Aviation Week reported on an independent study in 2016 which concluded that the demand is there. It suggested that as many as 1,300 aircraft worth $260 billion will be needed over a 10-year period.

The biggest potential market sector would be North America, said the report.

A decade from now, intercontinental air travel is likely to be very different. And, as Boom argues: “Every passenger wants faster flights.”