As someone who has actually flown on the Concorde, I can say that I'd gladly endure its tight seats again and empty my wallet in exchange for a shorter flight. Heck, if I had the option between spending $20,000 for a NY-London roundtrip on an Overture (the same price for that route on the Concorde, inflation-adjusted) versus spending $20,000 to charter a long-range private jet (likely a significant underestimate), I'd go for the Overture in most cases.

However, although I'm rooting for any company that's making a sincere (as opposed to fraudulent) attempt at bringing back supersonic travel, the hardest challenges may still be ahead for Boom. The biggest one is the need to find or build a new engine. They've recently redesigned the Overture to use four engines instead of two, which should ease required engine specs, but there's no engine that would meet the reliability, noise, fuel consumption, and dimension requirements for a supersonic passenger aircraft.

Related to the engines: money. It sounds impressive that boom raised at least $150 million, including $60 million from the US Air Force (which has the added advantage of creating a new customer segment in the military)... until you learn engine development alone would require in the ballpark of $6 BILLION of capital. Aviation history is rife with examples of amazing, innovative aircraft designs that failed because no suitable engine was available.

Also, Boom leadership has set some ambitious goals, which makes me a bit skeptical. They plan on using sustainable aviation fuel (SAF). Great! But now they not only need to create a new engine, they need to create a new engine that runs off of a new fuel. Additionally, they've set a goal price of $5,000 for a New York to London roundtrip whereas Concorde would've cost $20,000 for the same route. Heck, I once paid $8,000 for a Boston to Tokyo roundtrip business class flight. Nothing wrong with setting such a goal (and Boom isn't even the party that sets route prices) and it's OK for marketing claims to be a tad optimistic, but this tests the limits of credibility.

Lastly, there's the issue of possible routes, which is primarily limited by noise constraints. Unlike the Concorde, which needed afterburners to produce sufficient thrust for takeoff, Boom is going for a no-afterburner design. While this should expand the number of airports the Overture can use since afterburners won’t be blasting the neighborhood, you’re still not going to be able to fly over land. Boom suggest 500 routes are supersonically viable[1], which I’d assume means “pairs of international airports separated mostly by water”. We might be talking about something like 50 actual airports. only a fraction of those routes are not just supersonically viable, but economically viable. Of course, commercial aircraft are designed for particular types of routes. An Embraer ERJ-145 regional jet and the Boeing 787 long-range wide-body jet fly different routes. I’m not expert on this though; maybe 500 routes is plenty for a “total addressable market” in the aviation industry,

To bring it all together: my big issues with Boom are, one, engine development and, two, the choice of “hard problems” they decided to take on (specifically, SAF & cheap tickets). My hopes are that the engines are in development, using SAF instead of conventional fuel isn’t a big deal if you design for from the start, and the $5,000 thing is more about saying how low, hypothetically, an airline could price tickets while making money. I’d also like to know what the current status of the state-of-the-art is in quiet supersonic flight. NASA’s quiet supersonic demonstrator, the Lockheed Martin X-59 QuSST, combined with regulators’ desire to decide on supersonic overland travel in 2028, would open up new routes like JFK-LAX for planes meeting noise requirements, should regulators decide to allow it.

My hypothesis on Boom’s design choices? Quiet supersonic cruise is still technically challenging and has an uncertain regulatory future, and the political tide may be turning towards greater regulation on fossil fuels. So, by using SAF, Boom ensures that their plan will at least fly in an uncertain regulatory future, even if there’s no overland flight. And, using what they learned developing the Overture, they’ll be in a position to develop a quiet supersonic transport should regulators give the green light.

[1] I’d interpret routes to be something like airport-pairs, as in Laguardia-Heathrow would be one route. If you Boom could fly from three airports in the US to or from three airports in Europe, you’d have nine routes (3*3). This article talks a bit about the lack of clarity with Boom’s “route” number: <https://leehamnews.com/2021/06/04/hotr-500-destinations-for-...>