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Comment by epicureanideal | Hacker News Reader

Even if supersonic flight were 2.4x less fuel efficient than regular flights, based on Concorde vs other aircraft, if that translated into 2.4x ticket prices, a lot of people would still pay it.

$1000 vs $2400 to get to Europe in 6 hours instead of 12? A lot of people who just hate those long flights would pay for it, especially given that flights are only a portion of total vacation cost, together with hotels, etc.

Or for a flight inside the US, $1000 rather than $400, but to get from coast to coast in 3 hours rather than 6, may be very worth it for some people.

https://aviation.stackexchange.com/questions/107206/how-clos...

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Worth mentioning that no one intends to make commercial jets go Concorde fast (mach 2) again, to my knowledge.

Boom is talking about "Boomless Cruise" being up to mach 1.3. they are trying to bounce the downward going sound waves off the atmosphere, bouncing them back up. It seems to be significantly speed dependent? https://boomsupersonic.com/press-release/boom-supersonic-ann...

That’s only over land. They intend to go 1.7 (perhaps more) over the ocean.

What happens when there are 1000 flights over land all having sonic booms, and 1000 reflecting sonic booms, and the 1001 plane flies through all the sonic booms?

There are no sonic booms with this new aircraft. That’s the point.

They still make the booms - they're doing clever stuff to prevent the sound waves reaching people on the ground, they're not changing the laws of physics to magically silence it.

I actually worked in the same building as the people organizing this research. Now I'm drawing on decade-old memory, and the program may have changed in the interim, but at that time the research that would become the X-59 demonstrator was absolutely about eliminating the sonic boom. There is no law of nature that says you have to have a sonic boom when you break the sound barrier--there are in fact a lot of assumptions wrapped up in that outcome.

A sonic boom is what you get when a traditional solid, largely flat-ish airfoil pushes air smoothly through the transition to supersonic flight. Very ELI5, but during the transition the energy/noise being put into the air basically stops dissipating from the aircraft at the point of transition, and so all that noise clumps together into a shockwave.

The shape of the X-59 makes it such that the transition doesn't happen uniformly over the air surfaces of the plane at the same time. It does get a little noisier around the transition, but it not a shockwave at all.

If that's so then apologies, my bad - I didn't see any details in this NASA news so just assumed it was similar logic to Boom Aerospace, whose strategy I believe is to somehow make the boom noise aim away from the ground (partly directly, and partly by figuring out a way to make sure that sound waves heading downwards bounce off the atmosphere back upwards, so that the boom exists just not audible to people at ground level).

And TIL I learn that it's even possible to break the sound barrier without a boom of some kind (assuming NASA haven't found otherwise and adopted Boom's strategy in the years since you were hearing about it from them). Cheers for the interesting comment!

Edit: although I hope somebody can answer sroussey's original comment of «What happens when there are 1000 flights over land all having sonic booms, and 1000 reflecting sonic booms, and the 1001 plane flies through all the sonic booms?», since if Boom are successful I assume they're more likely to have thousands (or at least enough to have overlapping flights at times) of planes in the air than NASA. Unless, I guess, NASA do such a good job of demonstrating that you can actually get rid of the boom rather than just redirecting where the sound waves go that Boom change their strategy to that and/or get outcompeted by rival companies doing the NASA way. ("Just" is a little unfair, since Boom's technique seems incredibly clever to me.)

All good. I know less about Boom's technology, but yeah from what I understand they took a different approach: redirect the sonic boom up and out so that it it spends more time traveling through the atmosphere and isn't so loud once it hits the ground. The X-59 solution is to not make a sonic boom in the first place. You can't eliminate the noise entirely, but with the X-59 they talk about a "sonic thump" that is qualitatively of a different order.

It's a bit like stealth tech: early "low observable" fighter planes did things like switch to unibody cockpits so there were fewer reflective interfaces and therefore a smaller radar cross section. Then the F-117 and B-2 went with "be fucking invisible to radar" (or approximately so). Totally changes the game.

A "sonic thump" will be noisier than normal operating engine noise. You will hear it and it will be noticeable in the sense that unlike regular airplane takeoff and landing, it will be a distinct transitory sound.

But in terms of absolute noise levels and mechanical properties, the "sonic thump" of a commercial airline would probably be considerably quieter than, for example, the regular takeoff/landing noise of a military jet. It needs to be characterized and understood to see what the effect would be on communities living near supersonic airports, but not a real engineering concern.

Your question is valid with respect to Boom though, and that is part of their challenge to getting regulatory approval for supersonic transition over land.

The concord was heavily subsidised. Those ticket prices didn’t cover the cost of the service.

It was also far less pleasant a ride than even most economy class tickets for long hall flights. The space was more cramped and it was much louder inside the cabin. Personally, Id rather spend more for nicer seats on a longer flight than worse seats on a shorter flight. And a lot of people with money felt the same.

Design changes might help with the passenger comfort problem but when the plane is already running at a loss, it’s a hard sell asking for more R&D costs (which would be massive) to redevelop the concord.

This is something I've really flipped on when I started taking trains more to replace domestic flights (in Europe) to improve my personal CO2 footprint.

I used to be really impatient with travel and tried my best to save travel time, and never took the train. Then I forced my self to change my ways.

Nowdays, I find thst plan the train travel days as part of the trip: Sure, it takes me a whole day to get somewhere, but I allocate that time for hacking on the laptop on a side project, reading a book, or playing a game on the Steam Deck, things I normally don't find that much time for. I find e.g. my vacation satisfaction actually has gone up.

Train travel is also easier with (my) kids than air travel despite the longer duration, because you can roam the train more, change location to the restaurant, etc.

Hard agree. If you lean into it, it's a much more pleasant way to travel in many cases.

Everything about air travel is rushed, stressful, and unpleasant. Yeah, I can get there in 3 hours (if you account for the "show up two hours early in case we understaffed the check-in desk" thing), but by the time I get there I'm _wiped_. Plus I'm probably going to end up either leaving or arriving at some ungodly hour that means my sleep schedule's screwed and that's basically all I'm getting done that day anyway.

The train I take instead runs every 30 minutes. You can rock up 6 minutes before the train leaves and walk right on after someone scans a QR code. You can bring a drink! There's tons of space for people and luggage. The seats are huge. Your legs fit. The tray is big enough to actually work on. You can get up and go for a walk. There's a water fountain and water bottle filler. The washroom is bigger than some bedrooms I've had.

If you're traveling with kids you can actually book seats at a full-fledged table and have lots of room for activities and colouring and such.

And it takes 5 hours. So sure, in theory it's two hours longer. In reality, I've got back almost 5 hours of my day. And I can arrive at a reasonable hour and not tired and stressed to shit and actually do things with the rest of my time.

Last trip I used the way there for some relaxing. Did some reading, played some games, generally just wound down. On the way back I was able to get some work done effectively so actually got paid for my travel day. Either way, it was a much better experience.

As a someone who recently spent 13h in economy I would pay double for 6 hours

The types of people who could afford the concord weren’t the types of people who’d fly economy on a 747.

Also, concord is still louder and more cramped than economy on a typical long hall 747.

It was not more cramped than economy. I’ve been in a Concorde. Every seat was like domestic first class in the USA.

“In a” Concorde or “flew” Concorde?

The ones at air shows felt more specious than the commercial ones. Or at least that’s how it was from my admittedly very limited first hand experience.

Ok I don’t know the origin of the one I was in. It is the one exhibited at the Museum of Flight by the Boeing campus in Tacoma, Washington.

That doesn't at all match my experience.

I was fortunate to fly an Air France Concorde between JFK and CDG and, while the seats were leather (which was not the case in economy at the time), they were no larger than economy seats.

The windows were tiny and the cabin itself was also quite small. It definitely felt cramped.

I'm very unconvinced that real world pricing would actually work that way.

The price difference between direct and connecting flights, for example, already shows how much more expensive the convenience can be.

No, the Concorde was profitable for the airlines up until 9/11: https://simpleflying.com/did-british-airways-make-a-profit-f... https://etonomics.com/2025/05/14/the-economics-of-concorde/

The Concorde was a loss for the manufacturer, though.

I'd do it 1/10_000th the speed if I could, from an airship with a hotel glued to the bottom.

An air-yacht sounds awesome, especially if it could be made really safe and comfortable, and fly low enough that you can see the views. You may not even want to get off the yacht at all!

> Or for a flight inside the US, $1000 rather than $400, but to get from coast to coast in 3 hours rather than 6, may be very worth it for some people.

Don't those people already have access to private jets?

Do you know how big the gulf is between a first class ticket and a private jet? Having more options between those two would reach a huge market, especially if it saved time instead of just offering “luxury.”

I assume anyone that can afford a first class that isn't having it paid for by a company can also afford a ride on a private plane. They just choose not to.

What are you talking about?

LA to NYC first class (lie flat) on American = $3k LA to NYC on a super-midsize PJ (seats 8) = ~$50k

Even empty legs cost way more than this:

Miami to NYC on a Citation X = $24k

Not only that, but on a cross-country flight, the commercial first class is more comfortable than a midsize.

It depends how many people you bring on the private jet. Rich people usually come with quite the entourage. I'd imagine that becomes cheaper pretty quickly

It's not an incorrect statement, if for the flippant reason. To charter a jet, you pay for the jet in total not for individual ticket sales. So if you divide the jet's charter price by the number of people and each person chips in does become more feasible. Plus the amount of time you don't need to spend at airports waiting, going through security, waiting for baggage claim, etc. Private jets also fly faster than commercial, so there's an additional bit of time saving as well

Private jets fly faster? Both fly very close to the speed of sound, so they really can't fly much faster.

But yes that's what I meant, with a private plane you pay for the plane not per seat. I guess chartering a netjet would be cheaper than say 8 first-class seats.

Say you're a family of 5. You could be a set of dick parents and mom&dad get first class while sending the 3 kids into coach. Pricing whatever 5 tickets can add up quick. So even for a family it could become viable to charter a jet vs flying commercial. Again, you get the added benefits of such an easier airport experience.

And yes, private jets tend to fly faster. Yes, commercial jets can fly faster, but they don't as they have determined the most fuel efficient cruising speeds. Private jets are less concerned about that. You can see the same thing with your car. The faster you drive, the worse your MPG.

It’s not a lot faster though. They can also fly more direct routes sometimes, which also is a small gain.

I’ve looked at it a few times and flying private is just tantalizingly out of reach for a private vacation with a large family. Far less cost than you would expect (but still a 1% privilege).

Sounds like your top 10 Facebook friends to survive the zombie apocalypse doesn't have the right balance. You gotta have a pilot friend in the list. Mechanic friend, a knitter, a building trades type, a farmer/rancher type are all good. Drop lawyers, artists, coders. The choice is yours and the benefits are what you sow

It isn't the planes speed that makes private jets faster. It's the fact that you don't spend hours sitting on the tarmac at the destination waiting on an open gate. You drop the stairs, grab your bags, and walk out of the airport.

Did I mention private jets aren't subject to the TSA?

That aspect of being faster was already mentioned in the grandparent comment to yours. But it also said specifically that they also fly flatter, which is what the person you replied to was responding to.

Less than you think. A private jet is between $600 - $1000 per hour on the low end. That’s close to the numbers people here are talking about for resumed supersonic ticket prices, and certainly within range of the historical Concorde price.

Not for one flying cross-continent, which is what this is competing with. Go look up how much it costs to fly from LA to NY on a charter flight.

I’m talking about rented gulfstream jets. What are you talking about?

The Concorde and what I understand to be it's lack of viability was exactly what I was thinking about - it motivated my question. What's different now?

I remember seeing something from Boom (now renamed?) which was an YN company years ago. I recall them developing some technology to solve the noise problem - somehow bouncing the sound off the atmosphere or similar IIRC? I do think its viability has increased over the years, just everyone has this default "it wont work" mindset because of the failure that was Concorde.

the biggest difference is that composites and better computers probably make designing and manufacturing a good design a lot more feasible

IIRC the big issue was cooling the air into the engines. I think that is still a big issue.

The engines remain really tough, but using a properly tapering fusalage does let you increase capacity/thrust by 10-20% (and a lighter airframe helps here too)

They did fly them for 33 years. Even if it didn't work out in the end its not exactly an abject failure. I could imagine slightly better business plan, etc could make all the difference.

After all, concorde design started almost 75 years ago, surely we've learned a thing or two on how to design aircrafts with lower maintenance & operating costs in that time.

It lost money consistently all the time.

The only reason it kept flying for 33 years is a vanity project for national airlines.

Which it was excellent at. Actually viable business? Not so much.

Concorde made an operating profit. Not a huge one (how could it, with fourteen planes flying), and it didn’t recoup development costs, but it was in the green once that initial cost was paid.

Concorde never paid those initial costs, and had massive subsidies [https://www.nytimes.com/1981/01/09/business/france-extending...].

It was able to coast, eventually, but that’s some very fancy accounting.

“French Transport Minister Daniel Hoeffel, saying France ''will not and cannot abandon Concorde,'' signed a new agreement with Air France this week. The French Government, which with Britain had spent more than $2 billion developing the world's first supersonic passenger aircraft, will pay 90 percent of the plane's estimated operating losses for the next three years, compared with 70 percent in the past.

Under the new pact, the French taxpayer will contribute $66 million this year to the cost of Air France's champagne-and-caviar service linking Paris with New York, Washington, Caracas and Rio de Janeiro. In 1982, when losses are expected to decline slightly, the subsidy will be about $64 million, and in 1983, $59 million.”

Revenue exceeding ongoing costs after writing off development costs is not very fancy accounting.

It wasn’t just dev costs.

In my opinion, there are worse ways for governments to subsidize aerospace and materials research and development, improve the connectivity between nations, generate national prestige, give people optimism for the future, and so on. 2 billion doesn't sound like a lot. It's a drop in the bucket compared to US military expenditures.

If California High Speed Rail loses a little bit of money, I won't be too upset by it. Unfortunately the up front costs are much higher, but at the same time, massive, massive infrastructure development is happening in California all along the length of the state, and the government is acquiring the rights to develop public transportation both now and into the future on that land. Again, there are worse ways to spend the money in my opinion.

I am not sure if there are much worse ways, as this here means normal people subsidizing rich peoples luxory fast flights.

Bad for climate. Bad for the people below enjoying the noise. Bad for all the other things you could do with 2 billion. (A lot)

Only good for people who want jetting quickly around the World.

And it is good for material research, but that's the same argument for military development.

Bear in mind those are 1981 dollars.

Yes, the worse way is to just jail all the engineers and have them work while in the Gulag.

> It lost money consistently all the time.

> The only reason it kept flying for 33 years is a vanity project for national airlines.

Something that loses money, but not so much money that it can't be justified as a vanity project, seems like the sort of thing that could be profitable with tweaks and improvements.

Like it didn't work, but it was close enough to working that reasonable investors could say: second time will be the charm. Especially given how much more mature aeroplane technology is now vs the 1950s.

To put it in perspective, we first broke the sound barrier in 1947. People started designing the concorde in 1954 only 7 years later. It is now three quarters of a century later. Technology has improved a lot since then.

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