BOOM! Commercial supersonic airliners: will they succeed this time?


United has announced plans to buy 15 of Boom's Overture supersonic jets - but the deal is subject to the very strenuous condition: "once Overture meets United's demanding safety, operating and sustainability requirements".

When Concorde retired in 2003 it looked as if that was the end of supersonic air travel, which had only ever been for a very select group of people with Platinum corporate charge cards or very deep pockets.

The air transport business slipped into a period of technological regression as aircraft speeds actually declined, a period in which the only bright spot was the improvement in noise and gaseous emissions (along with some glimmers of profitability).

Suddenly, supersonic is back in the spotlight again, with a number of manufacturers hoping to bring into service - by way of a small bunch of enthusiastic airlines - aircraft that are not too dissimilar from Concorde. Indeed, unnervingly so, because Concorde never really paid its way and was the victim of extraneous factors even more so than the rest of the industry.

This report includes a look at the history of Concorde, where it went right and (mainly) wrong, and at how the world in which the proposed new versions will operate has changed dramatically over the last 20 years. This will influence how the new supersonic services would be received by the public, where they would operate, and the likelihood of them being a success this time around.


  • United Airlines and a handful of others have made (mostly non-binding) commitments to 80 orders and/or options for a new supersonic aircraft similar in range and performance to 'Concorde'.
  • There are other manufacturers too, but one has already fallen by the wayside, raising concerns about the future of the others - or clearing the way for them.
  • United was in need of some positive PR but appears determined to see this through, whatever.
  • The new aircraft's sustainability could win it much of the support that Concorde never had.
  • But is speed still as important as it apparently was then?
  • Which leaves the question of the aircraft's operating economics, and where it can fly cost-effectively. In that sense the route developers are starting with a clean slate.

Supersonic travel lasted 27 years, but could soon be on its way back

Supersonic commercial air travel lasted just 27 years, from Concorde's first flight in Jan-1976 until it was retired in Oct-2003.

Concorde began in a blaze of glory and supersonic bangs, promising London to New York travel in three and a half hours (at a trans Atlantic velocity that enabled Phil Collins famously to appear on both the 'Live Aid' stages, in London and Philadelphia in Jul-1985, courtesy of two helicopters and a scheduled British Airways Concorde flight).

More significantly, for a quarter of a century (including the era of the Wall Street 'Master of the Universe' stockbroker and the 'yuppie') Concorde carried hundreds of business people (it had a relatively small roster of regular users) between their own 'stages', enabling ultra-fast business deals face-to-face.

That ended with the disaster on the afternoon of Tuesday, 25-Jul-2000 that was flight AF4590 from Paris Charles de Gaulle Airport to New York JFK airport, when the aircraft hit a piece of metal on the runway, one that had fallen from a Continental Airlines' DC-10 moments earlier. The metal blew a tyre, a piece of rubber from which hit the fuel tank, causing a fuel leak and engine fire.

The Concorde crashed in flames in the village of Gonesse, killing all 100 passengers (who were German tourists on their way to join a cruise ship), all the nine crew members, and four people on the ground.

Despite the fact that previously its safety record had been second to none, with zero passenger deaths per kilometres travelled, and that significant safety improvements were made after the crash - when Concorde was grounded for 16 months - the aircraft's days were over.

On 10-Apr-2003 Air France and British Airways simultaneously announced that they would retire Concorde later that year, citing low passenger numbers following the crash, the slump in air travel following the Sep-2001 terrorist attacks in the US, and rising maintenance costs.

The nature of the supersonic business was already changing

The fact that AF4590 was carrying a full load of tourists on a charter flight suggests how its utilisation was changing.

Both BA and Air France were operating such charter flights - not because they wanted to, but because they had to: Concorde was otherwise failing to pay its way commercially, and seat supply was exceeding demand at an unacceptable rate.

Hardly surprising then that the round trip ticket price between New York and London or Paris was up to 30 times that of the cheapest option available sub-sonically.

Just 20 Concorde aircraft were built, of which only 14 ever flew commercially.

One major competitor to Boom's Overture has already pulled out

The world may have got even faster since Concorde retired, but it has got considerably 'greener', and economy has long overtaken speed on airlines' wish lists.

That is why Boeing (which designed the 300-seat B2707 supersonic project in the 1960s but eventually ceded in favour of Concorde, mainly on noise grounds) scrapped its 'Sonic Cruiser' design (which was slightly subsonic), one that first saw life as Concorde was being retired, in favour of a more fuel-efficient design, which ultimately became the 787.

So United appears to be out on a limb with this project, but in fact, that is not the case. There have been a number of credible proposals for the development of commercial supersonic aircraft.

Possibly the most credible case came from Aerion Supersonic, but that company announced it was ceasing operations on 21-May-2021, prompting some aviation observers to conclude that there is no plausible commercial future for this category of aircraft now - if there ever was.

However, only two weeks later, United Airlines surprised the aviation world by announcing a firm order for 15 supersonic airliners from Aerion's competitor, Boom Supersonic.

Unlike Aerion, Boom has a prototype aircraft ready to begin flight trials toward the end of 2021. Its production model has a planned-for 60-to-88 passenger complement, compared to only 10 for Aerion's proposed aircraft, which was a business jet and at the latter end of the scale, similar to Concorde's 100 seats.

Moreover, Boom's Overture airliner is to fly at Mach 1.7 (1.7 times the speed of sound, or in this case, 1,306 mph or 2,089 kph), compared with Aerion AS2's Mach 1.4. But that is considerably slower than Concorde, which could, and did, achieve speeds of Mach 2.02.

Aerion had 10 firm orders and options for 20 more. In comparison, Boom has United's 15 firm orders, another 35 United options, and options for 20 from Japan Airlines and 10 from Virgin Atlantic - part of a parent group that always strives to be at the cutting edge technologically.

Boom has a continuing relationship with Rolls Royce for engine development. Concorde was powered by Rolls Royce Olympus engines, which emerged out of long range nuclear bomber propulsion, although Rolls Royce has recently taken a GBP1 billion hit over its Trent-1000 engine problems.

A whole host of 'issues' awaits any latter day supersonic operator

Apart from the aforementioned issues of sonic booms and environmental sustainability, certification must be gained from the FAA and other agencies.

That would be no easy matter to start with, taking into account the Concorde crash (the cause of which is still disputed in some quarters). Even it was the first, there is the ongoing saga of the 737 MAX and various other types at this time, and the fact that there is no category in the FAA into which a supersonic aircraft fits.

Then there are potential health issues, for both passengers and crew, which are better understood now, such as the impact of a higher dose of extra-terrestrial ionising radiation because supersonic aircraft fly higher. This can be offset by shorter flying times, but the science is still not fully understood.

Furthermore, the potential for disaster when there is a sudden reduction in cabin pressure is enhanced when flying at 60,000 ft. The value of oxygen masks is reduced both for passengers and crew, who might pass out (hypoxia) in as little as 15 seconds. That is one reason Concorde was fitted with very small windows, to reduce the rate of air loss in the event of a breach. And returning to the subject of certification by the FAA, that body would have to recalculate emergency descent rates and procedures as it had to do for Concorde. No easy task in a crowded airspace such as in the US.

Speed is not the be all and end all any longer

But the most pressing issue is probably that of operating economics. They were bad enough to start with, but since the final Concorde flight a mindset has emerged that speed is not the advantage is was once thought to be.

Even if there is slow action to address climate change, both the potential passengers and the corporations who pay for them will be closely weighing up to what extent time travel savings of a few hours are worth the additional expense. And there certainly would be, even if Boom claims ticket prices on the Overture airliner might be comparable to current business class levels. This at a time when business travel is likely to be suppressed for some time to come. The ownership and operating cost of the supersonic plane will almost certainly be considerably higher than that of a 787 or A350.

There is a suggestion that United might 'cannibalise' some of its existing premium cabin business on routes where it offered supersonic service, effectively replacing a cabin on a larger aircraft with a separate smaller.

Another problem that has gone to sleep since the demise of Concorde, but which would have a rude awakening, is that of scheduling.

Many flights between the US and Europe, for example, are between slot-controlled airports. Slot 'pairs' that work for 7-8 hour flights (the typical length of a trans Atlantic flight) will not work for much quicker trips. The time saving that might be achieved could easily be offset by waiting times on the ground, which impact on the timing of connecting services.

As for those like Fred Finn, the world's most travelled man and the most frequent passenger on Concorde, often returning on the same flight he'd arrived on as it turned around - it wouldn't be worth the effort. He might as well travel subsonic and in much more comfort.

It should be remembered that Concorde was not a particularly comfortable aircraft to fly in, by any means. Apart from the tiny windows (see below) and the huge 358sqm delta wing area, which made it difficult see very much anyway, the overall wing-heavy design of the aircraft ensured that the cabin was narrow and cramped. A passenger wouldn't want to spend much more than three hours on it.

Another interesting little fact that United might want to note is that, in its early years at least, the British Airways Concorde service had a greater number of 'no shows' than any other aircraft in the fleet.

Which begs the question of what sort of overbooking profile is needed for an aircraft of 60-88 passengers when the vast majority of them will come from a highly specific and defined socio-economic group? There won't be many students hanging around on standby hoping for a spare seat to come vacant.

Apart from Boom there are two other start-ups that remain in the race to restart long haul supersonic commercial air service, but even despite Boom's endorsement by United and other airlines, there is no guarantee that any of them will succeed.

Other technologies exist that could render supersonic as 'yesterday's'

And then there is the prospect of more advanced technologies getting ahead of the game.

If there is a development of a 'second wave' of supersonic airliners, both technologically (Concorde took from 1954 to 1976 to get into the air commercially) and cost-effectively (effectively Concorde never did that), then there is every chance that it will have been rendered obsolete by the likes of Elon Musk's SpaceX, or its competitor Blue Origin, or some other competitor, just as hyperloop technology threatens to make dinosaurs out of existing 'high-speed' rail networks.

Few Concorde routes were consistent money makers

But what if Overture or any other such supersonic sub-orbital aircraft did actually make the grade? Where would it fly? Which routes would be suitable and how do they compare with Concorde's?

Concorde's limited route network reflected the socio-economic paradigm that related to the era in which it operated. The prestigious trans Atlantic routes connecting Paris/London with New York and Washington were the best known (Air France's Washington service didn't last long, just six years, and BA cancelled its service in 1994). These were routes that echoed with governmental, military and commercial power.

Other scheduled routes included Paris-Rio de Janeiro (via Dakar, Senegal), and London-Singapore, which was operated via Bahrain with dual BA/Singapore Airlines livery and with half of the cabin crew from each airline.

But that service lasted just three round trips because of noise complaints by the Malaysian government, which tried to use it as a bargaining tool to get more accessibility to London for MAS. The service resumed in 1979, bypassing Malaysia (with obvious difficulty), but only until 1980, when a dispute with India prevented Concorde from reaching supersonic speeds in Indian airspace.

Economics was the driver behind Air France's Paris-Mexico City service (via Washington or New York) in 1978-1982 during the Mexican oil boom, but a subsequent global economic crisis put paid to it.

Even when Concorde was operating it had to decelerate from Mach 2.02 (maximum speed) to Mach 0.95 to cross the state of Florida sub-sonically to avoid a sonic boom over the state.

In the US only Braniff rose to the challenge, Texan style

Domestically within the US, from 1978 to 1980 the Dallas-based Braniff International Airways leased 11 Concordes - five from Air France and six from British Airways - and used them on subsonic flights between Dallas-Fort Worth and Washington Dulles International Airport, flown by Braniff flight crews.

Air France and British Airways crews then took over for the continuing supersonic flights to London and Paris. The aircraft were registered in both the United States and their home countries; the European registration was covered while the aircraft was being operated by Braniff.

The flights were not profitable, and typically less than 50% booked, forcing Braniff to end its tenure as the only US Concorde operator in May 1980. The airline ceased operations altogether two years later.

BCal wanted Concorde for oil routes, but high oil prices put paid to that

British Caledonian Airways (BCal), which eventually merged into British Airways and which operated into Braniff's territory in Texas, also coveted a Concorde service, using one of the unsold aircraft.

It eventually opted to lease two of them, and one route it would have flown was the oil and expat-influenced London-Lagos route. Probably the other was Houston, so that it could connect these two major oil and gas centres via the financial capital of London, or possibly Atlanta, which was even then the US' principal hub airport; imaginative marketing for the time.

But (ironically) high oil prices brought about by the 1979 energy crisis forced BCal to abandon its supersonic ambitions.

Other routes operated included BA's London-Miami via Washington (1984-991), and BA also operated a once weekly London-Barbados service for the wealthy set who had Caribbean island homes (including by this time Virgin Atlantic's Richard Branson) for a lengthy spell between 1987 and 2003, when all Concorde services ended.

It was probably the success of this leisure-oriented service that prompted both BA and Air France to launch their Concorde charter business via third party tour operators, mainly in France and the UK, although the charterer of AF4590 was Peter Deilmann Cruises from Germany.

Charter could have been Concorde's saviour

Potentially charters could have become a global business, had Concorde found a way to keep flying. The charter business was beginning to be considered lucrative by both BA and Air France, and there had been charter flights to cities including Mexico City (where the scheduled service was abandoned in 1982) and Acapulco - another 'jet-set' destination that is awkward to get to, sub-sonically.

There are some places that Concorde should have travelled to, by hook or by crook, but it never did, apart from demonstration and promotional flights.

Because of the distances involved, Australia was at the top of many people's wish list. But Concorde was inhibited by its short range (which rose to a maximum of 7223 km/4488 miles), brought about enormous fuel usage that more than offset the extra-large tanks.

In order to travel from Western Europe to Australia, Concorde would have had to refuel twice, thus cutting into the time saving. Moreover, with only 100 seats (the original French preference was for 150 seats) other operating economics would have made a regular service economically unviable. in the meantime of course, seating on widebody aircraft has become much more comfortable too.

Just how far, as well as fast, Overture can fly is going to tax United and the other potential operators.

'Concordski' had limited ambitions

Another country that had very limited supersonic service was Russia.

The Soviet Union (as it then was) attempted to build its own 'Concordski' as it became known in the western media, the Tupolev Tu-144, which initially had a significantly shorter range even than Concorde. The Tu-144 was the world's first commercial supersonic transport aircraft, with its prototype's maiden flight from the then military Zhukovsky Airport (now Moscow's fourth commercial airport) on 31-Dec-1968, two months before Concorde's.

The aircraft had poor control at low speeds because of a simpler supersonic wing design, and even required braking parachutes to land as if it was a jet fighter or a space shuttle. The Tu-144 had two crashes: one, very visibly, at the 1973 Paris Air Show, and another during a pre-delivery test flight in May-1978.

In later versions the range was improved to close to that of Concorde. Initially the Tu-144 operated freight and mail services to Alma Ata (now in the independent republic of Kazakhstan), and that was also its only scheduled passenger destination as well.

Passenger service began in Nov-1977, but after the 1978 crash the aircraft was taken out of passenger service after only 55 scheduled flights; those flights had carried an average of 58 passengers. The Tu-144 programme was cancelled by the Soviet government on 01-Jul-1983.

Presumably the Soviets had far greater ambitions for the Tu-144, possibly for fast services from Moscow to Havana and Caracas (Aeroflot's subsonic aircraft used to refuel at Sal in the Cape Verde islands en route to those destinations, and 'Concordski' could also have done) - but it wasn't to be.

Concorde, and supersonic air travel, in general has had a chequered history, and there is nothing to suggest that the going will be any easier if and when it returns.

So what does this all mean? What lessons can be learned by future supersonic operators?

The Middle East cannot be ignored

Notably, the very first Concorde flight, operated by BA, was between London and Bahrain (albeit it was used as a refuelling post en route to Singapore later), and it is unthinkable that Middle East routes would not be part of the international picture today - at least, those involving Dubai and Qatar.

Indeed, it's not beyond possibility that Qatar could feature an early prototype supersonic version in its promotion of the 2022 FIFA Soccer World Cup in November and December of 2022, whether or not it was operated by Qatar Airways. Apart from the annual pilgrimage to Mecca it is the biggest mass attendance event happening in the Middle East in two millennia.

Maximum range and speed together only barely compare with that of Concorde

The second thing to bear in mind is the range of the Overture aircraft and other models which manage to cut the mustard. It seems that Overture's aircraft range will be in the order of 7,870 km maximum, which is not much greater than that of Concorde.

So, an aircraft that will be slower than Concorde but not able to fly more than a few hundred kilometres further without refuelling. That will limit the routes the aircraft can serve in much the same way that applied to Concorde. Not a great advance operationally in 45 years.

But 'sustainability' presses all the right buttons

One distinct advantage the aircraft will have is that it will be more 'sustainable', and hence, 'on message' with the corporate world.

The intention is that Boom's Overture aircraft will be a net-zero carbon producer from the get-go and will run on sustainable fuel (SAFs). Just how SAFs, which are still very much under development, square with supersonic travel and afterburners is not so clear, but at least the aircraft will be far more acceptable environmentally than Concorde would have been now, even if it makes a smaller bang. The drawback will be the (currently) much higher prices of SAFs and the limited sites where it is available internationally.

United being the main operator to have expressed an interest in Overture so far, the world will be watching where the airline starts to fly the aircraft first - assuming it does fly.

The aircraft's technical specifications suggest that its routes will be similar in nature to those of Concorde - i.e. premium ones with very heavy business usage by major corporations rather than SMEs, and also where there is a definable demand from 'high value' individuals, including 'celebrities'.

The end of the 'red-eye'?

Domestically, top of the route list would be the 'red-eyes' between the main commercial centres on the east and west coasts of the US, such as Los Angeles/San Francisco-New York, possibly Chicago in the Midwest.

Such services would lengthen the working day in both directions by two hours or more, and thus alleviate the need for overnight stops. 'The most comfortable hotel bed is your own', as the old marketing message has it.

Also, other commercial routes that are in great demand, or will be, such as Seattle-Miami. The former is an acknowledged home of digital technologies, while Florida is, for political reasons, experiencing a surge in population and businesses at the further expense of the rustbelt cities and states to the north.

United Airlines: domestic route map

US domestic routes, and potential ones involving Canada and Mexico, would not be impacted by range issues, but they would beyond that region. Trans Atlantic routes would be similarly restricted, but most of the important gateways could be reached from the US East Coast at least.

Point-to-point is in demand; hubbing will be less attractive in a post-COVID era

Fundamentally, supersonic routes existed to take passengers point-to-point between important places, not to 'hub' or 'interline', but there have been changes to the way the air transport business is marketed since Concorde.

The Star Alliance, of which United is a founder member, was initiated six years before Concorde's last flight in 1997, with oneworld (BA) following in 1999 and SkyTeam (Air France) in 2000, but Concorde was never really influenced by this new marketing methodology.

Any new supersonic aircraft today would be so influenced, even if the raison d'être for airline alliances has been questioned in recent years. Much thought would have to go into not only how other domestic subsonic services would benefit from a connection to an Overture flight, but how international ones would, too.

On the other hand, the COVID-19 pandemic has dictated that most passengers now seek out point-to-point methods of travelling between any two places, as rapidly as possible, and may even forego a journey altogether if none exists, so as to minimise 'exposure'.

Hubbing is less attrractive, and likely to take a great deal of time to find favour again. As far as business travel (and that of the independently well-heeled) is concerned, that could hand an advantage to supersonic travel that it did not have in its previous life, as long as ticket prices are reasonable.

While oil and financial centres will still figure on possible route lists, technology ones may be more dominant

Linking technological centres both domestically and internationally will be as important as was connecting financial centres and oil centres in the past (although demand will still emanate from those domains).

If the operating economics and mechanics are right, that could even mean the advent of 'round the world' routes linking the west coast of the US (Silicon Valley, Seattle) with 'Silicon Alley' in New York, Dulles Technology Centre in Washington, the 'Cambridge Cluster' close to the UK's Stansted Airport, the Rhine-Main-Neckar IT cluster in Germany (Europe's largest), others around Eindhoven in the Netherlands and Nice in France, 'Silicon Wadi' in Israel, Hsinchu City in Taiwan and Bangalore in India.

The supersonic aircraft might even find themselves carrying extremely high value IT-related (or medical) freight alongside the passengers.

It is not only United that might be attracted to such possibilities. Both the ever-ambitious Virgin Atlantic and Japan Airlines, which have attached themselves to Overture, would probably be too, together with Chinese airlines.

History dictates that charter flights need to be part of the business plan right from the start, not an emergency alternative.

On the other hand again, how much flying speed is actually needed today? Technology has moved on, including the simple expedient of being able to sign legal documents virtually and not to require the face-to-face contact, which is now regarded as undesirable anyway.

Some airports that would never have seen Concorde could be prospective recipients of the new supersonic order

Another aspect is what the impact of supersonic will be on airports now? These aircraft no longer have to fly into principal gateways and hubs as they did, although they probably will, all the same.

Some lesser ranking airports stand to make significant gains from such services though, and were mentioned or referred to above: London Stansted, Seattle-Tacoma, San Francisco and/or San Jose, Duesseldorf in Germany, Tel Aviv, Bangalore, as well as those that support any new centre of sustainable power generation.

As for handling the passengers, their demands are likely to be more acute than were Concorde's and their 'exclusivity' allied to the ticket price that has been paid will prompt them to insist on a far more personal approach on the ground than ever existed at airports in the 1970s and 1980s.

Some airports that have developed private terminals for scheduled commercial service passengers (rather than specifically for business jet users), such as Los Angeles, Singapore and Manchester, might have inadvertently built themselves an early advantage, even if refuelling plus a small number of 5th Freedom passengers was all they could realistically hope for.

A new breed of 'route developer' will be called for

The world is a much more complex place in many ways than it was when Concorde first took to the air, and even by comparison with what it was when the aircraft made its last flight.

It is not so much operating economics, fixed and variable costs, and demand forecasting that dictates air route decisions these days, so much as 'ESG' - Environmental, Social and Governance.

There have been few technological advances in aviation since Concorde that are worth mentioning, hence the return of supersonic travel is literally a case of 'back to the future'.

What is certain is that a whole new breed of route network developers will be needed, in airlines, airports and manufacturers, as very few remain from the first time around. Just as NASA lost the design plans for the Saturn V rocket so that we couldn't build one to carry a nuclear warhead into space if threatened by an asteroid or comet, the people who will have to decide how to operate this second wave of supersonic airliners efficiently will be starting from scratch.

All of that said, it needs to be observed that most new ideas - and this is new for its time - more readily find sceptics than supporters.

Thus far Boom's promoters have managed to navigate the headwinds of unbelievers and line up some highly credible partners, operationally and commercially. The industry is much bigger than it was in Concorde's day, as are the market segments that would be attracted to a supersonic operation later in this decade.

That would only leave the need to generate profits, something the airline industry still struggles to come to terms with.

Want More Analysis Like This?

CAPA Membership provides access to all news and analysis on the site, along with access to many areas of our comprehensive databases and toolsets.
Find Out More