Could all our future planes travel faster than the speed of sound? It’s been more than 20 years since the last supersonic passenger flight took off, but a US company wants to bring it back.

Boom Supersonic, based in Colorado, is developing the world’s first supersonic passenger aircraft since the demise of Concorde. While the full-size aircraft is still a few years away, the company has reached a milestone in the project when it successfully broke the sound barrier with its small-scale test aircraft on Tuesday.

The XB-1, affectionately known as the ‘Baby Boom’, is a one-third-scale demonstrator used to test the technology that Boom will employ in its full-scale aircraft. Yesterday, the XB-1 achieved Mach 1.05 within about 11 minutes of taking off.

“XB-1’s supersonic flight demonstrates that the technology for passenger supersonic flight has arrived,” Boom founder and CEO Blake Scholl said in a statement. “A small band of talented and dedicated engineers has accomplished what previously took governments and billions of dollars”.

The aircraft, which flew for the first time in March, is made almost completely from lightweight carbon fibre. It uses an augmented reality vision system to help with landing, since its long nose and high-angle approach can make it difficult for pilots to see.

“The future of aviation is here and now,” told Amy Marino Spowart, president and CEO of the National Aeronautic Association. “Not only is there hope for faster and better commercial flight, but Boom proves that it can be done sustainably”.

Boom’s Overture airliner will be the first supersonic passenger aircraft in more than two decades. But can it succeed where past efforts to get us travelling faster have failed?

A short history of supersonic passenger planes

Back in the 1950s, everyone was convinced that supersonic was the next big thing in air travel. Having just about mastered the jet engine, the aviation industry was inspired by Chuck Yeager, who was the first to break the sound barrier in 1947. Major manufacturers set about designing a commerical passenger aircraft that could do the same thing.

Boeing, certain that the mighty 747 would be the last subsonic aircraft it produced, began working on the 2707 SST (supersonic transport). Lockheed proposed the L-2000, a supersonic aircraft that could carry 250 passengers. However, neither aircraft went into production.

Just two supersonic passenger planes have ever entered service – the Russian Tupolev Tu-144 and the venerable Anglo-French Concorde. In total, 20 Concordes were built, although only 14 flew in passenger service. Russia built 16 Tu-144s.

The Tu-144 – affectionately known in the industry as the ‘Concordski’ – entered service in 1975 but was retired from passenger service just three years later. Concorde lasted longer, flying from 1976 until 2003.

So, why did aviation give up on supersonic passenger transport so soon?

What was the problem with Concorde?

The appetite for a supersonic passenger plane was strong. By the time Concorde took its first test flight, orders had been received for more than 100 aircraft from dozens of major airlines of the day. Pan Am, American Airlines, BOAC, and Lufthansa were counted among the many carriers keen to fly faster routes.

But even before the aircraft entered service with British Airways and Air France, many of these orders had been cancelled. Three main problems existed with the plane – noise, smoke, and money.

The 1973 stock market crash and an oil crisis in the same year made airlines rather cautious about aircraft that consumed a lot of fuel. Reports suggested that Concorde achieved a per-passenger fuel efficiency of 15.8 mpg (17.8 L/100 km), making it a rather thirsty option.

In comparison, the Boeing 747 would achieve a per-passenger mpg rate of 46.4 (6.1 L/100 km), and the popular Douglas DC-10 managed as high as 53.6 mpg (5.3 L/100 km).

Coupled with the worries about fuel consumption, the noise of Concorde’s sonic boom caused issues that made its planned routes with potential buyers unviable. Complaints of broken windows and cracked plaster from households under the flight path, and even farmers reporting panic amongst livestock, meant Concorde was banned from going supersonic over land.

As a result, the plane was forced to fly subsonic until it got over the open ocean. This meant Concorde’s high-speed routes were mainly focused between Europe and the USA, making the plane less attractive to potential buyers who wanted to operate routes over land.

In the end, only Air France and British Airways ever flew the Concorde. Putting the aircraft into passenger operation presented yet another challenge, however, as the costs to power such a fuel-hungry jet with a modest passenger load of around 100 people made the business case very weak.

In order to make Concorde profitable, both airlines had to charge eye-watering prices for tickets. According to the National Air and Space Museum, British Airways would charge around $12,000 (€11,550) for a round trip between London and New York. Adjusted for inflation, that shakes out to around $66,000 (€63,500) in today’s money.

The companies made a go out of it – just about. Despite the high costs, both airlines managed to sell tickets, with passengers seeing their trip as a ‘once in a lifetime’ opportunity. But the cabin was noisy, smelly, and cramped – hardly a luxury experience for the money.

The death blow came when an Air France Concorde was involved in a fatal crash in 2000. Debris on the runway was blamed for rupturing a tyre, which then punctured one of the fuel tanks. This caused the plane to crash into a nearby hotel, claiming the lives of 113 people.

While both BA and Air France cited high maintenance costs for the retirement of their Concorde fleets in 2003, there were many factors at play. In truth, the market had moved on, and a trend for low-cost flying and more efficient aircraft had made Concorde redundant.

Will Boom Supersonic succeed where Concorde failed?

If you believe the hype, Boom claims to have already dealt with many of the issues that contributed to Concorde’s demise. Noise, cost, and efficiency are high priorities for the company to tackle.

Part of Concorde’s noise profile was a direct result of the engines using afterburners to achieve supersonic flight. Overture will not use afterburners, which should significantly reduce fuel consumption and the associated noise.

For passengers, the cabin is a world away from the cramped, noisy environment on Concorde. Advanced soundproofing measures mean it shouldn’t seem any louder than a conventional jet aircraft, and the company has already floated some designs for its interiors that look suitably luxurious and comfortable.

The company has developed its own engine solution that it says will reduce fuel consumption. These engines are designed to run on 100 per cent sustainable aviation fuel which, although not available at scale yet, would further reduce its environmental impact.

Overture hasn’t quite managed to eliminate the sonic boom effect, but thanks to more optimised aerodynamics, the impact will be reduced significantly. The company promises that Overture will be able to fly over land at Mach 0.94, about 20 per cent faster than subsonic aircraft, without breaking the sound barrier.

For now, the supersonic aircraft would be restricted to breaking the sound barrier over water. Boom says there are more than 600 transoceanic routes on which Overture could provide a supersonic solution without changing current regulations relating to sonic booms.

“Overture was created to achieve optimal performance while meeting our stringent safety and sustainability requirements,” says Boom Supersonic. “We are leveraging more than fifty years of advancements in aerodynamics, materials, and propulsion to build economically and environmentally viable supersonic aeroplanes”.

But what of the market demand? By the end of Concorde’s lifespan, British Airways said it was selling only around half of its available tickets. Air France, still suffering from the tragic crash in 2000, was selling less, only around 35 per cent.

Concorde’s ticket prices were up there in the ultra-luxury category. In contrast, Boom is targeting business travellers, and pricing seats accordingly. Early estimates suggest a round trip Europe to USA ticket for around $5,000 (€4,800), in the ballpark of what passengers pay for business class seats on regular jets today.

“Today, there’s both the market demand and the technology to enable mainstream supersonic travel,” the company says. “Business and leisure travel has continued to grow, and travellers are willing to pay for speed.”

Boom is targeting 2029 for the entry into service of its Overture airliner. It has already had orders for 130 aircraft from multiple global airlines, including American Airlines, United, and Japan Airlines. If it can steer clear of the pitfalls that ended Concorde’s career, supersonic travel may well be back on the cards.