Relentless technological advancement underpins every aspect of modern life, but you can make a pretty convincing argument that air travel has gone backwards.

Sure, it’s very nice to have in-flight wi-fi, smarter lighting and multi-purpose touchscreen displays, but when the fastest possible journey across the Atlantic takes twice as long as it did in 1977, that’s regression by any measure.

Flying at Mach 2 (a mile every 2¾ seconds), the Concorde SST fleet enabled high-flyers to get from London’s Heathrow to New York’s JFK airport in less than four hours. Today, the same flight averages about seven.

BA’s senior Concorde pilot Mike Bannister once remarked to this reporter that the Boeing 747 planes flying beneath his 60,000ft cruising altitude appeared to be moving backwards. Sometimes, while aboard today’s cramped transatlantic flights, it feels that way too.

Since Concorde was controversially withdrawn from service in 2003, amid rising fuel and maintenance costs and slowing demand post 9/11, supersonic passenger planes have vanished from our skies - but they could finally be on the way back.

NASA investigates quiet supersonic travel

NASA and a number of companies in the private sector are seeking to overcome the barriers to financial and environmental sustainability that have kept us subsonic for the last 14 years.

“The absence of supersonic flight is not due to a lack of interest,” Peter Coen, the manager of NASA’s Commercial Supersonic Technology Project, tells in an interview.

“Since the demise of Concorde there have continuously been proposals, but the more serious efforts going on now reflect that tech is coming to a state of readiness.”

NASA is working with a number of partners to design and build a Quiet Supersonic Transport (QueSST) jet that won’t travel as fast as Concorde, but will be quieter, more affordable for passengers, and more environmentally friendly.

Nasa QueSST

The key for most interested partners is to minimise the loud sonic booms caused when aircraft break the sound barrier. Concorde flights were never permitted to fly supersonic over land because of this noise pollution, but if NASA succeeds, the sonic boom will be barely audible on the ground, if at all.

“Sonic boom mitigation in the design process has really been the focus of a lot of our work in the last five to ten years,” Coen says. “NASA views overland flight as the key barrier to having a product that airlines can use and integrate into their need to move the aircraft to wherever it needs to be.”

To help reduce the thunder-like sound, NASA plans for a jet that flies around Mach 1.8 (around 1,300mph), which is the “sweet spot for low boom design” according to Coen.

However, there’s more to the boom equation than simply speed. The length and aerodynamic shape of the aircraft and the number of passengers on board are also important factors.

Coen says: “At the time Concorde was being designed, people were writing down the first equations that outlined how you might go about creating a shape that might minimise sonic boom.

“We’re so far beyond that in terms of how we do the design and how we can shape all components of the aircraft in unison to achieve low boom.”

Nasa supersonic wind tunnel tests

NASA’s plans are still in the concept stages right now. In February, it tested a 9% scale model in 8ft x 6ft wind tunnel conditions (above). It aims to have a full-sized X-Plane (built by the military contractor Lockheed Martin) ready for its first demonstration in 2020.

Read more: Nasa is developing ‘quiet’ supersonic passenger plane

It is also seeking to negate the high altitude emissions that Coen calls “one of the biggest concerns” that evolved from the Concorde years. 

“We’re building on what’s been done with lean burn fuel injector development found in the newest crop of subsonic engines,” he says.

“We really think that an ozone neutral supersonic airplane engine is within the realm of possibility and that’s a clear focus area as well. We don’t want to do anything that’s potentially detrimental to the atmosphere.”

Supersonic commercial flights: Spike and Richard Branson’s Boom

NASA and its partners are far from the only parties with a keen interest in this sector. Spike Aerospace is a little further along with its plans for 18-seater business jets, which it believes can compete with current business class prices. It hopes to have a supersonic demonstrator in the air by the end of 2018.

At Mach 1.6 and 450mph faster than any commercial jet, the $80 million S-512 Supersonic would get the London to New York journey back down to three-and-a-half hours for just $5,000 return per seat (around £3,875). In contrast, a return ticket on Concorde during its farewell tour in 2003 was about £8,500.

So how does the firm plan to keep the costs affordable when flying only 18 passengers at a time? President and CEO Vik Kachora tells us his jet will achieve far greater fuel efficiency than Concorde, which burned a whopping 5,638 gallons per hour.

“If they were designing Concorde today they’d have the advantages of software that could optimise that aircraft to make it so much more fuel efficient,” he said.

“Concorde was an incredible aircraft, but at the time they weren’t worried about the sonic boom and they weren’t worried about the cost of fuel, which was 25¢ a gallon in 1960. We have to worry about those things now.”

The logistics of halving the flight time also make it possible get the price closer to a current business class ticket. A single crew could be used for both journeys, rather than having to put them up in the destination city overnight. “That’s a huge part of the cost,” Kachora says.

A third player in the race to reinstate supersonic flight is Boom. Backed by Sir Richard Branson, the company envisions 45-seater Mach 2.2 jets that, at 1,451mph, travel even faster than Concorde.

Boom concept plane

[Read more: London to New York in three hours? Supersonic passenger planes are closer to reality]

Its one-third scale XB-1 Demonstrator, which the company calls “history's fastest civil aircraft”, is under construction and will be tested in 2018. Successful demonstrations of its tech and swift approval from regulators could see the full-size passenger planes enter service in the early 2020s.

Boom is perhaps the most natural successor to Concorde because it’s targeting overwater routes (over 500 of them) at the fastest speed possible. However, like Spike, it also thinks London-New York can be achieved for $5,000 return, the current cost of a business class airline ticket.

“With the advent of modern technology, the time is now right for Boom to bring back commercial supersonic travel for the masses,” Erin Fisher, head of flight controls at Boom told us, “but this time at an affordable price point and with an efficient design.”

As with the other players in the sector, Boom believes it can bring down the costs by making the trip as fuel efficient as a subsonic jet through new design techniques, lighter construction materials and the newest propulsion technology.

“The Boom aircraft uses modern aerospace technologies,” Fisher adds. “Carbon fibre composites have paved the way for a more lightweight plane that can travel faster, safely. These carbon fibre composites, combined with turbofan engines help us achieve a significant improvement in fuel economy.”

Supersonic travel: The financial sustainability

Both of the private ventures from Spike and Boom hope to end the post-Concorde phenomenon of business class travellers paying five times as much to get there the same time as everyone else.

“What did we learn from Concorde? We recognised that people really valued time savings,” says Vik Kachora of Spike. “There certainly was a glamour factor, but for a lot of people it was critical to their businesses.

“As we talk to our customers, they’re excited at about the ability to go from London to Dubai and back on a day trip. You’ll be able to fly in, sign your deal, go shopping for a couple of hours and come back.”

Interior of Spike plane

The tragic Air France crash of 2000, which killed 113 people, may have spelled the beginning of the end for Concorde, but it wasn’t the main reason for its departure.

The fleet had a flawless safety record throughout its flight history and the fatal crash was the result of a freak chain of events. There was no risk in continuing to fly Concorde.

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Concorde pilots and engineers said peaks and troughs were natural throughout its lifespan and the halcyon days of regularly hosting A-listers and world leaders would have returned eventually, but at the beginning of the 21st century Concorde was a financial millstone.

It had become too expensive to operate and, towards the end, was flying across the Atlantic with less than ten of its 100 seats occupied.

The new breed of supersonic jets, while inspired by Concorde’s remarkable feats of engineering, believe new technologies and design tools have enabled the return of supersonic speeds in a way that’s financially and environmentally sustainable.

While the new jets may never recapture the sense of wonder and the affection felt for Concorde, by the middle of the next decade, the void may finally be filled.

Read more: Think you know Concorde? Test your knowledge of the iconic jet