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darkteflon 4 hours ago [-]
Cool science. But the article fails to take even a cursory stab at contextualising the plan against the economic, environmental and political backdrop - doesn’t even mention that there’s already been one failed supersonic commercial flight programme. This is as pie-in-the-sky as it gets.
hdndjsbbs 3 hours ago [-]
I think a lot of the Concorde failure is tied to its status as a British-French project. Trans-Pacific flights are much longer and there's a lot of money in PEK -> LAX than in JFK -> LHR.
Qantas wanted to offer London to Sydney, but they couldn't fly supersonic over land. Mainland China or Japan to Australia is a feasible route for high-margin, low-capacity supersonic flights.
If you could make the flight from Beijing to California take less than 5 hours that seems like a premium product many ultra wealthy people would spring for. Dubai to SFO is also a possible route.
vitally3643 58 minutes ago [-]
I was pretty sure the whole Concorde thing failed because people don't like it when you sonic boom an entire city dozens of times a day. And that all attempts to reduce the sonic booms necessarily resulted in flight times that aren't significantly faster than traditional subsonic flights, rendering the entire thing moot.
It was impractical due to physics, not some weird racism. You simply can't push a supersonic shockwave over inhabited areas, and the only way to not do that is to fly subsonic over land. Even if the oversea leg is supersonic, the tickets were much more expensive for not very much shorter flights. It wasn't a valuable proposition for most people.
godelski 28 minutes ago [-]
1) The flight markets are different now. There's been a large increase in both transatlantic and transpacific flights, especially the latter. These change the economics of considering only these types of flights, flying only over uninhabited regions.
2) The technology has changed. We're much better at dealing with sonic booms now. You can't get rid of them entirely, but you can reshape them. You can't send everything "up" but the longer of a tail you can make the more the sound dissipates by the time it hits the ground. There's lots of research around this and as you can imagine, incredibly important for the military. You can't fly fast spy aircraft if they are just announcing their position while flying around. Sure, there are satellites, but those are predictable by the enemy, you'll always need aircraft to do this.
Tuna-Fish 42 minutes ago [-]
However, there are markets where you don't have to fly supersonic over land, the distance is long enough for the speed to matter, and there is massive amount of demand. The only problem is, such markets require a longer range than what the Concorde was capable of. Notably, all the very frequently traveled trips over the Pacific.
toyg 37 minutes ago [-]
England in the '80s didn't give a shit about little people. Had it been really profitable, Concorde would have continued operations. It just did not make sense economically, particularly once they stopped making new airframes.
KennyBlanken 53 minutes ago [-]
It failed because the market dried up due to economic reasons, and they couldn't fill seats.
decimalenough 3 hours ago [-]
There is a lot of money in NYC-LHR, that's why Concorde continued to fly that route and profitably too, once they realized how high they could yank the prices and still fill the plane.
Also, Concorde's maximum range was 4,488 mi, which was calibrated to allow trans-Atlantic but not much more. Trans-Pac was not an option and even Australia to North Asia would be a stretch.
bobthepanda 2 hours ago [-]
I think they are agreeing with you re: the range.
There is money in NYC-LHR (it brings BA alone $1B in revenue annually) but the market for supersonic basically vanished. In the 70s when Concorde started flying, it was certainly a step up. However, the market niche basically disappeared when the lie flat seat was developed; for a lot cheaper, you could have a sleep for six hours in a really cushy lie flat, or you could spend a crapton more to be in a much louder, more cramped cabin for only about three hours less. If you were halving a 12-16 hour journey instead, there would still be a market left, but Concorde just didn't have the ability to do so.
mckn1ght 2 hours ago [-]
You can also essentially work remotely in an airplane now. I haven’t tried videoconferencing, but I easily do all my other software work on trips. So a couple extra hours might even be a benefit: more time with no distractions to wrap up that slide deck, maybe a 1:1 or two, get your free drinks from premium/business class, doze off to a movie, wake up for an early start at your destination.
XorNot 55 minutes ago [-]
12 hours on a plane is 12 hours on a plane. And there's currently no amount of ticket money that can make that shorter.
fragmede 34 minutes ago [-]
Shorter, no, but having a private cabin with a shower, and a lounge with a bartender on the plane, not to mention Starlink, would make those 12 hours a lot more bearable vs 12 in an economy seat.
steveBK123 23 minutes ago [-]
One analysis I read by a marketer that makes good sense is that the speed was worth paying for LHR to JFK but not really on the return given the clock changes and speed.
Getting to NYC before the clock time you left London was a cool trick. It allows you to make a morning meeting in NYC without coming in the night before.
But flying subsonic leaving NYC after dinner and arriving in London for breakfast works fine. Getting to London faster in 3.5 hours travel time but 8.5 hours later clock time means losing a day in the air effectively.
gottorf 3 hours ago [-]
> Dubai to SFO is also a possible route
Is there really that much premium traffic between Dubai and the Bay Area?
bobthepanda 2 hours ago [-]
The Middle East (was) a pretty common stopover for India flights, since India's not that well connected to the US due to a lack of capacity.
vidarh 1 hours ago [-]
A couple of searches suggests only Emirates operate a direct route between SFO and Dubain, so it wouldn't seem so.
rafram 41 minutes ago [-]
Emirates just dominates long-haul flights to Dubai overall. Other (mostly flag carrier) airlines handle other airports in the region. Qatar Airways through Doha is also a big player in flights between the US/Europe and Asia.
WorldPeas 3 hours ago [-]
I think the more interesting question is /will/ there be that much premium traffic ongoing
fakedang 1 hours ago [-]
Honestly not so much in my experience. It was busy, but mostly because of Emirates longhauls. Dubai to NYC and back is extremely busy though.
wat10000 2 hours ago [-]
Everyone thought SSTs were going to be the next big thing. Both the US and USSR had projects. The 747 got a hump so it could easily be converted to a freighter once it was made obsolete by supersonic passenger planes.
Despite two superpowers making the attempt, and plenty of time for more tries since then, Concorde is the only one that came even remotely close to something commercially viable.
I’m sure there’s a market for California to China in five hours. But is it enough to support a whole new type of aircraft? Fuel burn is going to be enormous. Maintenance on something so cutting edge will be extremely expensive. Tickets would probably cost more than a private room on a widebody.
stouset 2 hours ago [-]
You’re hinting at another huge part of the issue.
There are no economies of scale to be had here. If there are only a handful of plausible economically-profitable routes, all of the expenditures on R&D, testing, certification, and production facilities can only be amortized across a handful of aircraft.
Once you’ve built a dozen or two of them and a handful of extra engines and spare parts… what then? There’s no point in keeping the production lines open.
From an airline’s perspective, they have to now have an entire separate chain of employees (pilots, mechanics) dedicated to another airframe that barely makes up a fraction of their fleet. That’s a lot of overhead for two or three routes.
Those are some pretty big structural disadvantages that need to be overcome in order to make a boutique supersonic route appealing.
kevin_thibedeau 31 minutes ago [-]
Scheduled service is not viable but there is a bountiful supply of billionaires willing to one up each other with lavish expenditures. Having the fastest class of private jet is worth something to them. This is what's going to be the market for Boom if they don't fold.
VerifiedReports 3 hours ago [-]
ORD -> Vatican
KennyBlanken 55 minutes ago [-]
It's not tied to anything other than there not being enough people who care enough to spend the sort of money required.
The people who have that kind of money are going to be more interested in flying in a jet share doing mach .96 leaving when they want to leave, going where they want to go, when they want to go, how they want to go, with who they want to go with.
You get treated like a criminal for forgetting your shampoo bottle is 2 ounces too big for some dipshit TSA agent's liking, and meanwhile the ultrawealthy are shuttling around physical assets worth millions of dollars in their private jets and customs barely does more than stamp their passport.
toyg 39 minutes ago [-]
Yeah, this is something that changed from Concorde times (and possibly even sped up its very demise): the market for reliable, high-quality private planes has grown massively. It's now pretty easy to shuttle between the big cities in almost complete privacy through secluded airports.
_carbyau_ 12 minutes ago [-]
> This is as pie-in-the-sky as it gets.
I saw the "sounding rocket" and thought: Oh, hypersonic missiles money.
godelski 41 minutes ago [-]
> This is as pie-in-the-sky as it gets.
All your critiques are things we heard about Starlink too. "Oh, you're just reinventing Globalstar[0], which already failed. What makes you think this time will be different?" The question isn't wrong, per say, but most of the time it is used dismissively rather than in earnest. There's thousands of products you use today that were invented and ahead of their time. Hell, Google itself is famous for this. A great example being Google Glasses. When they first came out you could get punched in the face[1], but now there's Meta Glasses, Snap's, and dozens of others. The landscape changes, and fast. Just because others failed before doesn't mean others later won't.
It's not bad to ask these questions, but it is easy to be too dismissive. People love to tear things down, but not build them up. The two go hand in hand, but there needs to be a more measured approach. Frankly, projects can fail for many reasons. Too often it is simply bad luck. You either learn from the past or you repeat it.
I’m in favour of projects like these - even on spending taxpayer money on them. I think it’s super cool and I would love to see it. Yeah, I also think it’s extremely unlikely.
However, when you’re doing journalism, you should contextualise for your readers. TFA doesn’t even try to do the bare minimum.
rdl 2 hours ago [-]
Vastly more favorable today than it was when Concorde flew.
1) Rich people are WAY richer, and time is even more valuable
2) Businesses have some very important employees and "2 day trip" vs "3-4 day trip" is worth $50-100k
3) Larger population of people able to pay $20-30k for a flight than ever before.
The biggest practical impact is there's probably going to be a private jet version instead of just a commercial one, and there will likely be transpacific demand exceeding transatlantic. Also government/military use.
deadbabe 2 hours ago [-]
What are some examples of employees so important you would pay $100k to get them somewhere immediately?
infecto 2 hours ago [-]
You are not thinking high enough the food chain. I mean heck you have tenured SV engineers cracking $1mm with RSUs. It’s not rare in finance for folks to be hitting $3-5mm with bonus. So that’s what $19k comp a day. If that individual is making $5mm they are more than likely making a multiple of that for the organization.
bobthepanda 2 hours ago [-]
Even these days, a lot of retailers operate fleets of private jets even for district or regional managers, because it saves somebody like Walmart a lot of paid hours to fly someone from rural town A to rural town B rather than potentially deal with the hassle of an overnight booking at an airport hub.
1 hours ago [-]
Nesco 2 hours ago [-]
American execs negotiating memory two months ago in Korea?
amanaplanacanal 2 hours ago [-]
I think the SpaceX plan for point to point travel might be even more pie in the sky. Or maybe a tie.
bob1029 1 hours ago [-]
I think it's more practical. They've already got humans flying.
Snafuh 27 minutes ago [-]
Good luck getting a launch and landing pad anywhere close to a population centre.
Logistics around the flight would be a big asterisk behind the flight time.
jojobas 45 minutes ago [-]
Point to point rocket travel was never a good faith pitch, it was a hype thing (and your pension money are going into the fraud soon).
HNisCIS 3 hours ago [-]
Whenever you look at supersonic or hypersonic commercial aircraft plans you should assume one of two things.
A. It's a bait and switch by a founder who wants to pivot to weapons/military aircraft but wants to be able to hire high grade talent without paying the "we're gonna kill people" premium, can pivot once a good chunk of the workforce is complacent with a paycheck. You laugh but this happens SO FUCKING MUCH.
B. It's for business jet scale operations for billionaires. There are >3000 billionaires and however many corporate aviation departments and if you can build a super/hypersonic private jet that's not horribly expensive to operate the "time savings"* for that class of person will demand they buy one.
* when I say time savings I mean dick measuring contest
nradov 3 hours ago [-]
Defense contractors don't pay premium wages. Rather the opposite. Many employees specifically want to work in the field in order to contribute to the national security mission.
HNisCIS 3 hours ago [-]
I'm being a bit obtuse here to make the point, it's more complicated than that. The reality is if you create a defense startup you end up hiring defense employees which comes with its own set of issues.
That said, go look at salaries right now in the defense space.
picture 3 hours ago [-]
From my experience with working for defense/aerospace companies as well as civilian b2b ones in the US, the general situation is that defense/aero companies pay less but demands less of a grind. People usually take the lower pay (usually 70% of equivalent role in commercial sector) for the better culture
HNisCIS 3 hours ago [-]
For pure generic full-stack-whatever devs yes. For EEs, embedded, FPGA, RF, etc you can pull waaaaay more in the defense world, especially if you're willing to do cleared work.
nine_k 2 hours ago [-]
But if you need clearance to do your work, how can it be bait-and-switch? You need to hire people who are able and willing to obtain a clearance.
bigfatkitten 2 hours ago [-]
And have work that allows employees to keep their existing clearances active.
HNisCIS 2 hours ago [-]
Two different discussions, but I've had an earthy crunchy employer ask me to put in for one once.
Seattle3503 3 hours ago [-]
What companies are examples of that bait and switch strategy?
switchbak 25 minutes ago [-]
I’m not in the industry, but I would say Hermeus would be a perfect example. Ostensibly building a commercial airliner, but if you look closely it feels like a military oriented startup from the inside out.
nine_k 2 hours ago [-]
Google tried to become a national security contractor, and the backlash among the engineers was very intense.
Can't give any examples but I have definitely heard the same about a lot of aerospace startups through the grapevine. As for OP's point about private jets, Boom supersonic is your classic example.
HNisCIS 3 hours ago [-]
I can't name names but 3 of the startups I've worked at.
Places I haven't worked:
Skydio
Applied Intuition
Saildrone
Planet Labs
Boom
Scale AI
Also worth noting that sometimes it's on purpose, sometimes the founders are all "we're gonna save the world" then AFWERX enters the chat with a big fucking check and the founders yell "Nevermind! Guess we're the baddies now! How many slaughterbots did you say?"
Grosvenor 3 hours ago [-]
> * when I say time savings I mean dick measuring contest
And in this case smaller is better?
loeg 3 hours ago [-]
Safety should probably also be considered.
brandelune 31 minutes ago [-]
Two news items in one : Japan is getting ready for hypersonic missiles, and Japan’s elite does not give a damn about global warming.
argimenes 24 minutes ago [-]
The world's elites have factored in global warming already. It's a cost they are happy to shift onto their descendants.
ranyume 19 minutes ago [-]
>Their descendants
I'm sad to tell you, they're already looking for places on earth to buy land to build their nest after they decimate or help decimate humanity.
laughing_man 32 minutes ago [-]
Boy, that's an evergreen headline.
jjtheblunt 36 seconds ago [-]
that headline uses a modal verb mood "_could_ <verb>" and those titles are seemingly always clickbait
nubinetwork 2 hours ago [-]
I've always wanted someone to bring back the Avro Arrow to use the Iroquois engine for freight, but I don't think anyone has the knowledge to even pull it off anymore.
switchbak 21 minutes ago [-]
I’d love to have a big die cast model of one, but that’s about as close as we’ll ever get to the Avro flying again.
I don’t think you’d be pushing much freight on an Arrow (though I’d love to fly one!).
An XB-70 with modern engines? Now that would be interesting.
Padriac 2 hours ago [-]
I imagine passengers will be exposed to very high noise levels during flight.
BurningFrog 2 hours ago [-]
I don't have a good intuitive feel for that.
At 25km altitude, with 1% of normal atmosphere, maybe you're close enough to vacuum that it can get really quiet?
pdonis 2 hours ago [-]
The engine noise can still be conducted through the body of the plane. With the kind of ramjet being talked about, I think that's still likely to be significant even at very high altitude.
atoav 4 hours ago [-]
The actual time to skim off IMO is all the airport procedures.
jonners00 12 minutes ago [-]
And the time wasted on transfers. I used to regularly fly from airports in NY, London, SF, Singapore, LA, Sydney, etc. I would block out the opportunities to work or rest, and the reality was that only the plane time was valuable for either. It was painful to see all the other blocks of non productive time, particularly the allowances for congestion and disruption between downtown and the airports. I would have paid thousands a flight to be able to check in/clear security at my hotel and then get driven to a holding bay at the airport, and then on to the gate, in a vehicle suitable for both work and rest.
whiplash451 3 hours ago [-]
This is already a solved problem for the class of customers they are going after.
rafram 38 minutes ago [-]
Really? Obviously it varies by country, but there’s no customs/immigration when leaving the US, and security usually takes <5 minutes with PreCheck. Sometimes immigration takes a while on the other side, but it’s quick at airports with biometric gate systems. You still hear people talk about airport buffer time in units of hours, but I think that’s increasingly out of date.
wat10000 2 hours ago [-]
Not necessarily for extremely long haul flights. The airport side of things takes about the same amount of time regardless. For a transpacific flight, you’re looking at maybe 3-4 hours at the airport and 10+ hours in the air. Shaving down the airport side would be nice but a faster plane could save a lot more time.
superkuh 4 hours ago [-]
>At that elevation at Mach‑5, air around the nose and leading edges can reach temperatures exceeding 1,000 degrees Celsius (1,832°F), a challenge...
It is not the conical nose or leading edges that are the show stopper problem(s). There the shockwave generally does not touch the craft. The internal shockwaves that touch the walls of the engine ducting are. The heat loading and heat soak ability on those shockwave impingement sites will limit the duration of hypersonic travel.
Hypersonic travel through the atmosphere is easy, a problem solved in the 1950s. Be conical and carry your oxygen internally. Hypersonic travel that is air-breathing is an entirely different class of problem and I don't think it is anywhere near to being solved.
The only silver lining is that at hypersonic speeds you don't need to be propulsive for very long to get anywhere.
switchbak 18 minutes ago [-]
Supposedly the SR-72 has figured this out. Just rumours at this point, but apparently they’ve cracked the hypersonic air breathing puzzle on a usefully sized aircraft.
holoduke 4 hours ago [-]
What would a ticket cost like? 50k? Aren't those people in their own fancy private jet with whiskey, massages and party?
Ekaros 3 hours ago [-]
Or have their own room in first class... Maybe time trade off isn't worth it for most of the people who can afford it at that point.
3 hours ago [-]
Insimwytim 2 hours ago [-]
[dead]
domoregood 3 hours ago [-]
Ahh, but can it run DOOM...?
3 hours ago [-]
protocolture 1 hours ago [-]
[flagged]
rbanffy 4 hours ago [-]
People say this like it's a simple engineering problem.
No. By itself, a new hypersonic engine can't make 2-hour flights between Japan and the US a reality. We are not even close to being able to build an aircraft that can do that - we don't even have the materials for that. What seems "easier" (as in "less impossible") is a hypersonic glider design that enters a suborbital trajectory and does shuttle-like aerobraking while it glides to its destination, before reengaging propulsion prior to landing on an airstrip (because passenger planes need to be able to abort landings and do multiple attempts). Not sure how reverse thrust would work there - variable geometry rocket bells?
kelseyfrog 2 hours ago [-]
How long of a weightlessness period does this entail?
nine_k 2 hours ago [-]
Maybe not complete weightlessness, because at 80-90 km the atmospheric drag is still noticeable. But it should be enough of a unique experience.
Qantas wanted to offer London to Sydney, but they couldn't fly supersonic over land. Mainland China or Japan to Australia is a feasible route for high-margin, low-capacity supersonic flights.
If you could make the flight from Beijing to California take less than 5 hours that seems like a premium product many ultra wealthy people would spring for. Dubai to SFO is also a possible route.
It was impractical due to physics, not some weird racism. You simply can't push a supersonic shockwave over inhabited areas, and the only way to not do that is to fly subsonic over land. Even if the oversea leg is supersonic, the tickets were much more expensive for not very much shorter flights. It wasn't a valuable proposition for most people.
2) The technology has changed. We're much better at dealing with sonic booms now. You can't get rid of them entirely, but you can reshape them. You can't send everything "up" but the longer of a tail you can make the more the sound dissipates by the time it hits the ground. There's lots of research around this and as you can imagine, incredibly important for the military. You can't fly fast spy aircraft if they are just announcing their position while flying around. Sure, there are satellites, but those are predictable by the enemy, you'll always need aircraft to do this.
Also, Concorde's maximum range was 4,488 mi, which was calibrated to allow trans-Atlantic but not much more. Trans-Pac was not an option and even Australia to North Asia would be a stretch.
There is money in NYC-LHR (it brings BA alone $1B in revenue annually) but the market for supersonic basically vanished. In the 70s when Concorde started flying, it was certainly a step up. However, the market niche basically disappeared when the lie flat seat was developed; for a lot cheaper, you could have a sleep for six hours in a really cushy lie flat, or you could spend a crapton more to be in a much louder, more cramped cabin for only about three hours less. If you were halving a 12-16 hour journey instead, there would still be a market left, but Concorde just didn't have the ability to do so.
Getting to NYC before the clock time you left London was a cool trick. It allows you to make a morning meeting in NYC without coming in the night before.
But flying subsonic leaving NYC after dinner and arriving in London for breakfast works fine. Getting to London faster in 3.5 hours travel time but 8.5 hours later clock time means losing a day in the air effectively.
Is there really that much premium traffic between Dubai and the Bay Area?
Despite two superpowers making the attempt, and plenty of time for more tries since then, Concorde is the only one that came even remotely close to something commercially viable.
I’m sure there’s a market for California to China in five hours. But is it enough to support a whole new type of aircraft? Fuel burn is going to be enormous. Maintenance on something so cutting edge will be extremely expensive. Tickets would probably cost more than a private room on a widebody.
There are no economies of scale to be had here. If there are only a handful of plausible economically-profitable routes, all of the expenditures on R&D, testing, certification, and production facilities can only be amortized across a handful of aircraft.
Once you’ve built a dozen or two of them and a handful of extra engines and spare parts… what then? There’s no point in keeping the production lines open.
From an airline’s perspective, they have to now have an entire separate chain of employees (pilots, mechanics) dedicated to another airframe that barely makes up a fraction of their fleet. That’s a lot of overhead for two or three routes.
Those are some pretty big structural disadvantages that need to be overcome in order to make a boutique supersonic route appealing.
The people who have that kind of money are going to be more interested in flying in a jet share doing mach .96 leaving when they want to leave, going where they want to go, when they want to go, how they want to go, with who they want to go with.
You get treated like a criminal for forgetting your shampoo bottle is 2 ounces too big for some dipshit TSA agent's liking, and meanwhile the ultrawealthy are shuttling around physical assets worth millions of dollars in their private jets and customs barely does more than stamp their passport.
I saw the "sounding rocket" and thought: Oh, hypersonic missiles money.
It's not bad to ask these questions, but it is easy to be too dismissive. People love to tear things down, but not build them up. The two go hand in hand, but there needs to be a more measured approach. Frankly, projects can fail for many reasons. Too often it is simply bad luck. You either learn from the past or you repeat it.
[0] https://en.wikipedia.org/wiki/Globalstar
[1] https://www.cnet.com/tech/services-and-software/google-glass...
However, when you’re doing journalism, you should contextualise for your readers. TFA doesn’t even try to do the bare minimum.
1) Rich people are WAY richer, and time is even more valuable 2) Businesses have some very important employees and "2 day trip" vs "3-4 day trip" is worth $50-100k 3) Larger population of people able to pay $20-30k for a flight than ever before.
The biggest practical impact is there's probably going to be a private jet version instead of just a commercial one, and there will likely be transpacific demand exceeding transatlantic. Also government/military use.
Logistics around the flight would be a big asterisk behind the flight time.
A. It's a bait and switch by a founder who wants to pivot to weapons/military aircraft but wants to be able to hire high grade talent without paying the "we're gonna kill people" premium, can pivot once a good chunk of the workforce is complacent with a paycheck. You laugh but this happens SO FUCKING MUCH.
B. It's for business jet scale operations for billionaires. There are >3000 billionaires and however many corporate aviation departments and if you can build a super/hypersonic private jet that's not horribly expensive to operate the "time savings"* for that class of person will demand they buy one.
* when I say time savings I mean dick measuring contest
That said, go look at salaries right now in the defense space.
https://cloud.google.com/distributed-cloud-air-gapped
https://www.defence.gov.au/news-events/releases/2025-12-19/d...
Places I haven't worked:
Skydio
Applied Intuition
Saildrone
Planet Labs
Boom
Scale AI
Also worth noting that sometimes it's on purpose, sometimes the founders are all "we're gonna save the world" then AFWERX enters the chat with a big fucking check and the founders yell "Nevermind! Guess we're the baddies now! How many slaughterbots did you say?"
And in this case smaller is better?
I'm sad to tell you, they're already looking for places on earth to buy land to build their nest after they decimate or help decimate humanity.
I don’t think you’d be pushing much freight on an Arrow (though I’d love to fly one!).
An XB-70 with modern engines? Now that would be interesting.
At 25km altitude, with 1% of normal atmosphere, maybe you're close enough to vacuum that it can get really quiet?
It is not the conical nose or leading edges that are the show stopper problem(s). There the shockwave generally does not touch the craft. The internal shockwaves that touch the walls of the engine ducting are. The heat loading and heat soak ability on those shockwave impingement sites will limit the duration of hypersonic travel.
Hypersonic travel through the atmosphere is easy, a problem solved in the 1950s. Be conical and carry your oxygen internally. Hypersonic travel that is air-breathing is an entirely different class of problem and I don't think it is anywhere near to being solved.
The only silver lining is that at hypersonic speeds you don't need to be propulsive for very long to get anywhere.
No. By itself, a new hypersonic engine can't make 2-hour flights between Japan and the US a reality. We are not even close to being able to build an aircraft that can do that - we don't even have the materials for that. What seems "easier" (as in "less impossible") is a hypersonic glider design that enters a suborbital trajectory and does shuttle-like aerobraking while it glides to its destination, before reengaging propulsion prior to landing on an airstrip (because passenger planes need to be able to abort landings and do multiple attempts). Not sure how reverse thrust would work there - variable geometry rocket bells?