By the end of the 2020s, Concorde will have been a museum piece for as long as the revolutionary British Aerospace-Aerospatiale jet was in service – 27 years between 1976 and 2003. Yet, despite the venture’s commercial failure, the West’s only supersonic airliner (the Soviet Tupolev Tu-144 rival was even shorter-lived) remains an inspiration for those keen to deliver faster-than-sound flights to travelers once again, perhaps before the new decade dawns.
Leading the charge is Boom Supersonic, which is exhibiting at NBAA-BACE for the first time. Unlike its erstwhile counterpart and one-time NBAA-BACE regular Aerion, Boom is targeting the airline market – its in-development Overture jet will have 64 all-business class seats, not far short of Concorde’s 100. However, the company says recent milestones – including its XB-1 flight-test aircraft breaking the sound barrier six times without creating a sonic boom on the ground – makes “now a great time to engage with this audience”.
Boom – which last year opened its factory at Greensboro’s Piedmont Triad airport in North Carolina, also home to Honda Aircraft – says its “boomless cruise” feature will allow Overture to fly 50% faster than conventional aircraft over land and twice as fast over water. The company, launched by tech entrepreneur Blake Scholl in 2014, also hails as a landmark President Trump’s executive order earlier this year to direct the Federal Aviation Administration (FAA) to repeal a 52-year-old ban on supersonic flight over the USA.
While Boom says it “does not currently plan to build business jets”, it wants to develop a “family of aircraft… to meet the global demand for supersonic travel”. It says it is “supportive of opening up competition in the space” and that the lifting of the restriction could “drive innovation in supersonic travel, not only for commercial but also for business jets focused primarily on overland routes”. It adds: “There is overlapping demand with passengers whose time is valuable, and who want supersonic for both coast-to-coast and overseas travel.”
Boom says its research among business- and first-class travelers suggests that “desire for supersonic travel is incredibly strong” with 87% of premium passengers willing to switch airlines from their preferred carrier to gain access to supersonic travel. It predicts an “addressable market” for over 1,000 Overture aircraft but says those forecasts may be conservative because they do not take “demand stimulation” into account. Air travel to Hawaii, for instance, grew sixfold in the 10 years after jets replaced turboprops in the 1960s, it says.
However, unlike during the advent of the jet age, established airframers are not racing to embrace potentially disruptive technology, either in the commercial or business aviation world. Airbus, whose predecessor Aerospatiale co-developed Concorde, Boeing and Dassault, with their experience of building supersonic fighters, Bombardier, and Gulfstream have all dismissed the possibility of developing a supersonic passenger aircraft – something Scholl suspects is because none of them want to undermine their “cash cow” market.
Traditional engine manufacturers too have said no. Rolls-Royce – which developed Concorde’s Olympus 593 with Snecma (now Safran) – was Boom’s original partner but they parted ways in 2022, the UK company insisting a supersonic engine was not a priority, and Boom that the version of the Trent being offered was unsuitable anyway. GE Aerospace, which had been designing the Affinity for Aerion, ended its supersonic efforts after the latter’s 2021 collapse. Aside from military jets, Pratt & Whitney has shown no interest in supersonic propulsion.
This has left Boom with the unenviable task of developing and certificating its own supersonic engine, something Scholl characteristically believes is entirely doable. The company hopes to begin initial ground runs of its Symphony engine by the end of the year at its test site in Watkins, Colorado. Initial examples of the 40,000lb (177kN)-thrust engine will be assembled at the San Antonio, Texas facility of Standard Aero, which Boom began partnering with in late 2022.
Ten months after its inaugural subsonic sortie, Boom achieved the first supersonic flight of its one-third scale XB-1 demonstrator at the Mojave Air & Space Port in California in January this year. The jet, powered by three GE Aerospace J85-15 military engines, reached an altitude of just over 35,000ft before accelerating to Mach 1.122 (652kt). It was, according to Scholl, the first time an independently developed jet had broken the sound barrier and demonstrated that “the technology for passenger supersonic flight has arrived”.
While the Overture may not offer the cocoon-like privacy, comforts, and security of a private jet, Scholl firmly believes that its speed – M1.7 as opposed to its original promise of M2.2 – will be alone enough to tempt time-poor businesspeople, especially on key transcontinental and transatlantic routes. One crucial feature, he believes, is that it will do away with the dreaded ‘red-eye’ west-to-east flight as passengers will be able to depart early in the morning from the USA and, after a 4h trip, be in Europe in time for a late afternoon meeting or dinner.
Boom is targeting a first flight in 2027 and service entry by the end of the decade. While that sounds ambitious, given the Symphony prototype has not yet emerged, Scholl insists achieving “boomless” supersonic flight with the XB-1 confounded sceptics and showed how serious Boom is about disrupting the industry. After announcing an early flurry of “pre-orders” from airlines, Boom says it is now focused on certification rather than boosting its orderbook, believing Overture will sell itself once it achieves supersonic flight.
Some distance behind Boom is Atlanta-based Spike, which in August announced “significant progress” on the development of its supersonic business jet project, the S-512 Diplomat. After keeping a low profile for several years, founder and chief executive Vik Kachoria says the company is now “completing an enhanced study” to refine the roughly 20-seat jet’s aerodynamics, cabin configuration and low-boom performance.
Spike has already built two 2m-long scale prototypes which “showed we were on the right path”, says Kachoria, who founded the business 12 years ago. The company is now developing a one-tenth-scale demonstrator, chiefly to test control surfaces, with Kachoria highlighting this as a challenge. “At lower speeds, control surfaces are different than they are at supersonic speeds. Right now, we don’t have enough control surface for subsonic speeds, so we are playing around with that,” he says.
Like Boom, Kachoria welcomes Trump’s executive order on overland supersonic flights, which he says will open key markets such as New York to Los Angeles. However, unlike his competitor, he believes a smaller supersonic jet is the right solution. “With a smaller fuselage diameter, the sonic boom is lower. I’d love to go to 50 passengers, but the sonic boom is just unacceptable,” he says. Likewise, with speed, he insists M1.6 is the “sweet spot”, adding: “We would go faster but the higher temperatures make it difficult.”
He expects airlines as well as corporate flight departments to be among the operators of the Diplomat. With business-class seats becoming more commodious, airlines find it hard to command a higher price for first class, given that those premium passengers arrive at their destination at the same time as their fellow travelers in economy. “By replacing those 18 seats with a service that reduces a seven-hour flight to three-and-a-half hours, then airlines really can offer their most valuable customers a point of difference,” he says.
Kachoria is reluctant to put a target on service entry, admitting the project “has taken longer than I expected” and that he has had his fingers burned by stating dates that have come and gone. While the development is “much further along than we were three years ago”, raising funds is still a hurdle, especially with start-ups in emerging segments such as space and advanced air mobility competing for investment.
While he has no doubts that there is a market eager for supersonic air transport, he concedes that technological challenges remain, including quieting the sonic boom and reducing emissions. “That’s what takes so long,” he says. “We have been flying supersonic in the military since the 1960s, but the military doesn’t have to worry about fuel, or noise, or emissions, or for their passengers to have a great experience.”
One defence company trying to solve that conundrum is Lockheed Martin, which hopes this year to fly its X-59 quiet supersonic demonstrator, developed with NASA. The GE Aerospace F414-powered jet completed its first taxi tests in July. The X-59 is the centrepiece of NASA’s Quesst mission, which aims to demonstrate quiet supersonic flight by reducing the sonic boom to a “thump”. Regulators will use community responses from trials to formulate noise regulations for supersonic commercial flight over land.
Other would-be supersonic jet developers have left the stage. They include Los Angeles-based Exosonic, which shut down last November after running out of money. A few months earlier it claimed to have completed a “conceptual design review” of its proposed 70-seat airliner. Meanwhile, nothing more has been heard of Virgin Galactic’s design for a delta wing, 19-seat supersonic jet capable of reaching three times the speed of sound, after revealing in 2020 that it was working with Rolls-Royce on the project.
The highest profile casualty, however, has been Aerion, which began the development of its pencil-shaped AS2 business jet a few years after Concorde’s last flight but collapsed in 2021. Aerion had just begun building a global headquarters and assembly plant in Melbourne, Florida and had secured GE as an engine supplier, fractional ownership operator NetJets as a marquee customer, and financial backing from Boeing. However, after being bankrolled for 15 years by Texan billionaire Robert Bass, the company failed to secure fresh investment.
The experience of several failed developers of very light jets in the 2000s and AAM pioneers in recent times proves that – without the deep pockets of an established aerospace manufacturer and/or government backers – disrupting air travel with new designs and technologies is difficult. Even the most modest projects require sustained funding worth billions, not millions, of dollars to bring them to fruition, and trapdoors to oblivion wait at every turn of the funding journey.
As they continue their efforts to bringing supersonic travel back to the airways – and with support from NASA, the FAA, and the President himself – Boom and Spike believe this time it will be different and the fundamental need for speed among corporate travellers will drive the demand that will help make their concepts a reality.
