Concorde flew its last commercial service on 24 October 2003. For the twenty-three years since, the fastest way to cross the Atlantic has been slower than it was in 1996 — an almost unique reversal in the history of transport. Aviation is the only major mode of travel that got slower.
Boom Supersonic, founded in Denver in 2014, exists to undo that. And unlike the parade of supersonic startups that produced nothing but renders, Boom has now done something undeniably real: on 28 January 2025, its XB-1 demonstrator broke the sound barrier over the Mojave, reaching Mach 1.122 at 35,290 feet. It was the first independently developed supersonic jet in history, and the first civil supersonic aircraft built in America ever to go supersonic.
That is a genuine milestone and it deserves credit. It is also, in the brutal arithmetic of aircraft certification, the easy part. Here is where the comeback actually stands.
The aircraft: Overture
Overture is designed to cruise at Mach 1.7 at up to 60,000 feet, carrying 64 to 80 passengers in an all-business-class cabin, with a range of 4,250 nautical miles — roughly 7,870 km. It is a tailed delta with four medium-bypass, non-afterburning engines slung in external pods, built largely from carbon composite, and designed to run on 100% sustainable aviation fuel.
The most striking thing about it, if you put the numbers next to Concorde, is how familiar it looks.
| Concorde | Boom Overture | |
|---|---|---|
| Length | 61.66 m | ≈61.3 m (201 ft) |
| Cruise speed | Mach 2.04 | Mach 1.7 |
| Passengers | 100 | 64–80 |
| Range | 7,222 km | 7,870 km |
| Cabin | Cramped, loud, first-class fares | All-business, business-class fares |
| Over land | Banned — sonic boom | Targeting Mach 1.3 'Boomless Cruise' |
| First flight | 2 March 1969 | Not yet flown |
| Built | 20 (14 production) | 0 |
Overture is almost exactly Concorde's length. It is slower, carries fewer people, and flies slightly further. That is not a failure of ambition — it is the entire strategy. Concorde's Mach 2.04 forced it into exotic materials, afterburners and a fuel burn that only made sense with first-class fares on a handful of routes. Dropping to Mach 1.7 keeps the airframe in aluminium-and-composite temperature territory, allows conventional non-afterburning engines, and — Boom argues — brings the economics down to something an airline can sell as business class.
The catch nobody can engineer around: the engine
When Boom went looking for an engine, Rolls-Royce, GE, Pratt & Whitney and Safran all declined to build one. The capital cost of a clean-sheet supersonic engine, for a market of maybe a few hundred aircraft, did not add up for any of them. So in December 2022 Boom announced it would build its own — Symphony, a 40,000-lbf medium-bypass turbofan.
This is the crux of the entire programme, and it is worth being precise about where it stands. Symphony passed a key technical review in March 2026 that released it into manufacturing. Boom says roughly 95% of the parts for the first prototype core are in production. The core — a 12-foot, 4-foot-diameter high-pressure spool of compressor, combustor and turbine — is due to be assembled around mid-2026 and then run at Boom's own test site at the Colorado Air & Space Port, with the validation campaign later in 2026.
As of mid-2026, the engine that Overture depends on has not yet completed a full core test run.
No aerospace startup has ever certified a clean-sheet airframe and a bespoke engine simultaneously. Boeing and Airbus, with vastly greater resources and institutional experience, routinely take a decade to certify one or the other. Boom's public target remains entry into service in 2029 — CEO Blake Scholl reaffirmed it at the AIAA Aviation Forum on 11 June 2026. Independent analysts, including Forecast International, expect the date to slip into the 2030s. Both things can be true: the programme is real, and the timeline is optimistic.
The regulatory wall — and the crack in it
Since 1973, US federal regulation 14 CFR 91.817 has banned civil aircraft from exceeding Mach 1 over land. It was written in response to the sonic boom, and it is the single biggest reason Concorde could only ever be an ocean-crossing aircraft. Without overland routes, a supersonic fleet's network economics shrink dramatically.
In June 2025 an executive order directed the FAA to remove that ban and replace it with a noise-based standard. That is a genuine opening — but as of spring 2026 the FAA had still not published a final noise certification rule, and had not published a completed type certification plan for Overture. The door is unlocked; nobody has walked through it yet.
Boom's answer is Boomless Cruise: flying at around Mach 1.3 at an altitude where the shockwave refracts upward and never reaches the ground — a real physical effect known as Mach cutoff. XB-1 demonstrated it, going supersonic six times without a boom being heard below. It is clever, and it is also conditional on weather and atmospheric conditions, which makes it a scheduling variable rather than a guarantee.
The plot twist: Boom is currently selling power stations
The strangest development of the last year has nothing to do with aeroplanes. Boom took the Symphony core — designed to run at high temperature for hours of supersonic cruise — and repackaged it as Superpower, a 42 MW industrial gas turbine for AI data centres, sharing roughly 80% of its hardware with the aviation engine.
The orders arrived immediately. Crusoe placed a $1.25 billion launch order for 29 turbines, over 1.21 GW of generating capacity. A $300 million funding round followed, led by Darsana Capital with Altimeter, ARK Invest, Bessemer, Robinhood Ventures and Y Combinator. Boom says this is the remaining capital it needs to finish Symphony and continue Overture's certification.
Read that carefully, because it cuts both ways. The optimistic reading: the AI power boom is funding the supersonic airliner, and every hour the turbine core runs on a test stand is an hour of data for the engine that will fly. The pessimistic reading: the fastest-growing part of a supersonic aircraft company is now a business that has nothing to do with flight, and management attention is finite.
And the rest of the field
Boom is not alone. NASA's X-59, built by Lockheed Martin's Skunk Works to prove that a sonic boom can be softened into a 'thump', made its first flight on 28 October 2025 and had completed nine flights by April 2026, working up to around Mach 0.95 — it has not yet gone supersonic. Its results are meant to inform the FAA's future noise rules, so in a real sense every supersonic airliner is waiting on it.
Further out, Hermeus received an FAA special airworthiness certificate in March 2026 for Quarterhorse Mk 2.1, a step toward an eventual Mach 5 aircraft. That is a different order of difficulty entirely, and a much longer horizon.
So: is it coming back?
Honestly? Probably — but later and slower than the press releases suggest, and that is not the insult it sounds like. A demonstrator has flown supersonic. A factory exists. An engine is in manufacturing. Three airlines have reserved 130 delivery positions. Every one of those is more than any supersonic project has assembled since the 1960s.
But the orders are non-binding commercial interest, not firm capital. The engine has not run. The FAA has not written the rule. Certification has not started in earnest. Any one of those could add years, and history says at least one of them will.
The realistic read from mid-2026: expect Overture in the sky as a prototype before the decade is out, and expect fare-paying passengers in the 2030s. It will be slower than Concorde, quieter than Concorde, and — if Boom is right about the economics — it will do the one thing Concorde never managed, which is make money.
Concorde was a technical triumph and a commercial catastrophe. The comeback will only count if the next one is the other way round.