I wonder how lengthy charge cycles will affect the viability of fast turn times, especially for the short-haul segments that they're targeting for these new airliners. It seems like they'll need to either have extremely fast charging or be prepared for significant downtime between flights; where will the planes be stored while they're charging?
It's important to both invest in and appear to be investing in the future, but even a soft commitment of 100 planes seems like quite a bit, especially in the very competitive and cost-focused short-haul space.
0. https://www.npr.org/2015/06/28/418147961/the-man-who-saved-s...
But planes go between very limited sets of known points, with huge amounts of infrastructure. Adding in the capability to do Al-air battery swaps / recycling would be easy, and the benefits for the use case (huge weight savings, faster turnaround times by swapping vs charging) are big.
They are swappable though: they explain that used battery packs can be replaced and that used packs can be used for a second purpose with less stringent requirements. For example, an energy storage facility at the airport.
Why not do both?
Swap one part and charge just the internal batteries. But internal batteries does not sound so clever with limited lifetime anyway.
The security check in, long ticket lines, etc. are all byproducts of security theater that has come through and honestly in the US, with TSA Pre, I'm pretty sure I spend more time sitting at the gate than ANY other process (check in, 5 min, security, 5 min, walking to gate, 5 min, sitting at gate waiting for boarding, 40 min)
100% agree that the ability to walk straight into a train, find your seat through multiple doors (even the wrong car) feels pretty good.
The big advantage of the train is being on the property ladder 100 years early.
Since the planes themselves are really small, they also won't spend a long time at the gate so they could be transported to a maintenance hangar to recharge.
If anything, these shorter routes are more time-sensitive.
Alternatively, maybe they could swap out the bottom of the fuselage or wings.
Depending on how things work out, in 10 years we might see a lot more flights in 10-30 seat electric aircraft, e.g. as connecting flights to tiny airports.
Get a fleet of 2-4 seater unpowered glider planes [1]
Get a bunch of rural properties spaced ~100km apart.
Put little glider landing and launch strips on each property. Use a powerful electric winch to launch the gliders.
Develop software that can fly the planes autonomously from strip to strip (I assume this is the really hard part, but I am under the impression that autonomous flying is a much easier problem than autonomous driving?).
You now have the ability to shuttle passengers around your network of airstrips at ~200kph for the cost of electricity used by your winches and maintenance of the glider fleet.
My thought is that the electricity of the winches is pretty minimal and could be served with some locally installed solar panels and batteries, and the maintenance is super low since the gliders don't have many moving parts onboard.
The main use-case would be city-to-city short hops that are currently poorly served by rail. It's far easier to build a string of small airstrips than a whole rail corridor.
This idea came to me when thinking about SpaceX's recent plans to catch their Starship boosters out of the air instead of having landing gear on them. The reasoning is that you can have essentially unlimited mass for ground support equipment, but mass on the booster is precious. So you offload the landing gear from the booster to the ground support equipment, even if it's big and complicated. This idea is like electric aircraft, but you've offloaded the propulsion and batteries to the ground support equipment.
Electric motors are generally much simpler in construction and wouldn't need nearly as much mechanical inspection.
The difficult/expensive part is the battery, but that's going to have more onboard condition monitoring and will be simply replaced periodically, not subject to regular teardown inspections. The cost of ongoing battery replacements might be significant, though.
https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Commu...
The physics in Tom Murphy's textbook https://dothemath.ucsd.edu/2021/03/textbook-debut suggests it's impossible. I've talked to people at electric plane companies who have offered no hope.
I originally thought since we engineered from the Wright brothers to 747s, aren't we just at the Wright brothers stage now, but am starting to conclude it's not possible.
https://www.youtube.com/watch?v=RDtduvin9Mw
There's almost nothing to inspect or maintain.
https://online-learning.tudelft.nl/courses/sustainable-aviat...
It highlighted a few Bay Area startups. Sounded like smaller commuter planes would be first. There were also hybrid designs, which reduced fuel use significantly.
https://www.popsci.com/story/technology/electric-vehicle-bat...
Someone is. What is very interesting about Harbour Air's approach is that they are not creating new aircraft but rather retrofitting electric propulsion onto their existing fleet. This is not an electric engine filling a niche application. Rather, this is electric replacing combustion engines on very longstanding commercial routes.
https://www.harbourair.com/harbour-air-magnix-and-h55-partne...
"After the successful first flight of the Harbour Air eBeaver powered by magniX in December 2019 and the ongoing flight tests since then, the companies have teamed up with H55 to bring their shared vision of clean, efficient and quiet commercial aviation to life by 2022. H55 will provide its proven modular battery technology to expand the eBeaver’s balance to weight ratio and endurance. The company’s battery modules have one of the highest energy densities on the market and will provide the entire energy storage system and redundant battery monitoring at the cell level for the eBeaver. "
This means much less efficient flight, because lift costs energy, or much slower flight. But it's more plausible for these very short flights than for longer flights.
Solar-powered synfuel seems like a more likely mass alternative for the near future (02030-02050).
The eng dealt with:
The standard was scripts with mutable variables such as `G == , B == , C == , redefine G as something else later` responsible for the processes around pretty critical airplane innards.
QA down to 1 or 2 headcount, and those 1 or 2 also doing the above program writing.
Zero hand-off once leaving the job on the mission critical QA the eng was responsible for, not for lack of effort on the engs part. Managers not aware the eng was leaving until day-of.
I could go on and on, but the point: I'm not sure how I feel about the safety of airplane travel after the above, but at least the engines were internal combustion so somewhat tied to physics vs. programming logic. A future with electric airplanes scare me a bit though. The software in them is aggressively, poorly done. I know airplanes are designed w/ fail-safes on the fail-safes and that eng had their own limited view of a complex system. But, it was bad.
However, I'm pretty sure any modern internal combustion engine will have a highly advanced ECU computer too, so this is sort of a non-issue (though I'll admit I don't know much about aircraft engines specifically).
[1] https://en.m.wikipedia.org/wiki/Switched_reluctance_motor
[1] https://leehamnews.com/2021/07/01/the-true-cost-of-electric-...
You can also imagine that planes will start operating longer routes and then move to shorter routes as the battery degrades. Since the batteries are large they could get a decent amount of money for them when they’re too degraded for airplanes. They should still be useful for energy storage.
I also think it’s likely that when airplanes go mainstream, they’ll use a different chemistry than the standard Li-ion chemistries we have today. Maybe solid state lithium (Quantumscape?) or sodium ion. So it’s very hard to say how big the degradation problem will actually be.
Turboprop engines like the PT6 have a Time Between Overhauls of about 3000 hours, maybe longer. At 240 knots, that's 720,000 nautical miles between overhauls. If your electric aircraft has a range of 500 nautical miles and a 1500 cycle life, that's the same time. For an electric aircraft with a 900kWh battery like the Eviation Alice, and a cost per kWh of $170-$300/kWh, that's $150,000-300,000, the same as a turboprop engine overhaul.
Cycle lifes well beyond that are feasible, though, and battery costs are reducing over time.
The battery model will weigh at least twice that for the same useful work, so how the hell does it fly as far? Could it actually fly the mandated 100 nm + 30 min contigency*
By 2025 batteries are not going to cost 3x more than they cost today.
Even if batteries have to be replaced that often now, the technology will continue to improve, becoming both cheaper and more reliable.
Computers used to be the size of rooms and break due to literal insects in them.
Maybe he hires a writer, but his sarcastic joking nature comes off as extremely sincere and authoritative. This makes me question how solid his Wendover points are. He has a commanding voice and we believe him.
doesn't help that it feels like clickbait, at least for HAI, and most of them can be summed up with a tweet.
PS, I had to vouch for your comment to reply, as it was dead. Had a look through your profile… I think there's often a lot of value in asking simple questions, but a lot of your comment history is just extremely low value (eg. correcting people's spelling). If you don't have anything meaningful to add to a discussion, maybe consider not replying at all.
This has a huge potential, but I don't know if it will improve overtime, since energy density of Li-ion is a hard limit.
In fact i'd say europe could avoid airplanes entirely if it could sort out it's rail network, but, alas, going from Londom to Prague I'd have to change like 6 trains. You have to cross many different national signalling systems, gauge sizes and ticket offices.
https://www.flightglobal.com/aerospace/harbour-air-to-resume...
Drastically reducing fuel costs.
Let's suppose for a moment that air travel today worked the way you described it, with gliders, 60 mile range, electric winches etc.).
Then someone comes along and invents the motorized plane and now all of a sudden you can start and land a plane pretty much anywhere you want, you're no longer dependent on weather and, in addition, you multiply your range by a factor of 5x to 10x.
To me that sounds more disruptive than the other way around, so your idea would unfortunately fail the reversion test.
Honestly, for short ranges, you're much better served by electric planes, or gliders with a self-launch motor. Small strips and winches don't go together.
This assumes thermals are available in the area (some days are better than others, as are some locations), and the s/w knows how to ride them.
But that is a much harder problem than just launching and gliding.
Also, gliders that could carry even a handful of passengers + baggage would be huge, and likely far too heavy for a simple winch lift.
As for the automation - airliner flight is more or less a solved problem, for flights in good weather that don't suffer any emergencies.
It hasn't been taken further because most passengers don't want to fly without a human in charge. And also because the edge cases - unexpected turbulence, difficult weather, mechanical failures, unruly passengers, software failure - happen often enough to be a problem, and they need someone trained on board to take over.
Otherwise people die. And that's very bad.
Some problems with this scheme come to mind quickly but these are the first few:
1) Weather. It exists and basically makes this plan totally unworkable on any practical level.
2) Physics. An unpowered glider would have at best 1/100th the potential energy to fly distances like the ones you describe assuming perfect weather. Remember there are hard limits on altitude (due to oxygen) and speed (need to not rip the wings off) and those plus weight are the variables in your equation that tell you how far your glider can get unless it’s able to exploit unpredictable thermals.
3) Refundancy, or lack of it. The failure mode for the slightest miscalculation is certain death for your passengers and maybe a few on the ground. Unpowered flight leaves essentially no margin for error which makes it a non-starter.
Flying in good conditions may be an easier problem to solve than driving in good conditions but the issues seem to move towards what happens in the bad conditions. It's not like you can just hit the brake or park on the side of the road and continue later when the system detects a current or upcoming problem. Even if you get it so 99.99% of flights are in favorable weather and wind without piloting issue a 1 in 10,000 chance your glider is going to make an emergency landing or worse is not good enough odds, especially if it's multiple flights each way. And that ignores the problem of the service being unavailable if certain weather conditions aren't met, so the backup transportation option is still needed at a moments notice in full force anyways.
Then, much like self driving, there are the regulation issues https://www.ssa.org/glider-pilot-ratings/ which would be their own challenge to change and require you solve them before the business can even get it's chance to get going.
That being said I like the concept, just not sure it's really any easier. Perhaps we should just build the missing rail instead :).
As a software developer, this part is what I don't like.
We're still quite a ways from fully autonomous driving cars (as in: don't rely on a human taking over for backup). A bad bug in an autonomous car could drive you at high speed into a wall, but there can at least be an "emergency stop" button that disables the main processor and jams on the brakes.
Planes have no such ability to just "stop". At best, they could deploy a parachute, but even then landing safely is by no means guaranteed.
I think we need a decade or so of fully autonomous cars being accepted into daily life before this can be attempted with anything that flies.
We're (much?) closer to Fully-Self-Flying planes than FSD cars because the problem space is - perhaps counterintuitively - MUCH smaller to tackle. And we have a lot more experience tackling it.
Additionally there could easily be remote pilots as backup in case of catastrophe (See remote piloted military and border patrol UAVs)
And pulling a parachute at 1000'+ altitude actually has quite a bit of precedent (See https://en.wikipedia.org/wiki/Cirrus_Airframe_Parachute_Syst...)
Now... There's probably a lot of cultural and regulatory reasons why the "string of automated glider ports" idea will never come to fruition.
But... As far as technical hurdles go, there's not much new technology that would need to be invented here.
-- I don't know of any glider mass-produced after WW2 that seats more than two individuals, ± a water/sand ballast tank, ± a range-extender or self-launching engine.
-- Have you ever experienced a winch launch? Try it. It's about 3g of acceleration, sometimes more. I quite like them. Most normal people probably wouldn't.
-- At the top of the winch launch, you pretty much need to immediately find a thermal and gain some height before flying off cross country. You've got about a minute or two to do so, before entering the circuit and needing to re-launch and try again.
-- Replace "200 kph" with "about 80 kt IAS". Remember that gliders fly beneath the weather 99.9% of the time and the winds in clouds are strong -- although the only youtube videos I've seen of an aircraft landing "backwards" on a runway are of a Russian high-wing aircraft, it's entirely plausible that you could end up getting a negative tack speed in a cloud.
-- Cloud flying, or flying in inclement weather is insanely dangerous for a glider. They're relatively light, have large aspect ratio wings, and don't usually have a whole lot of instrument navigation equipment on board. If the wings are wet, their coefficient of lift goes down...which would have very bad consequences for your business model. There's a reason that cross-country glider pilots have a friend with a land rover and a trailer, and train to land in fields, after all.
-- You have absolutely no opportunity to make a go-around in a glider landing. Zilch. Nada. Screw it up and Plan-B is a well placed field. This is less likely to be acceptable commercially.
The energy would probably be better spent on a bus, with even a gas-powered bus being more efficient per passenger-mile than a 4 pax aircraft. It could also go city to city and skip the rural areas altogether.
Gliders are able to bypass this limitation in certain scenarios (such as updrafts) but this only works in specific cases. It also usually takes more than a launch to bring them to sustainable altitude, and they are slow.
Also, gliders are not really able to handle emergencies that well since they are unpowered -- if there's a need to divert or something, they're completely at the mercy of their own gravitational energy. Gliders are usually very safe to fly in because they're very light and maneuverable, and crash-landings are usually OK. That safety net completely evaporates with thousands of pounds of human cargo.
I guess it could be easier in some ways, still the idea of passenger UAV(?) seems insane for some reason
They proposed stuff like putting steroids in water supplies to make Canadians stronger. One of their propositions was to build an inclined bike road across Canada so you could "coast from coast to coast."
I am mainly curious if the general physics and economics of the idea are remotely feasible, assuming the software is solvable.
To answer your cargo question: probably not much. The distance is within a normal delivery range of some rural UPS/Fedex/DHL routes. Making people in these smaller cities go to the airport to pick up boxes just makes a lot of work for them.
source: my own experience taking loud proppy planes between Roanoke VA to Charlotte, NC to connect to a larger flight
How about trains for those distances?
I actually think you the cargo aspect will be somewhat significant as well- The regional airports I checkout on flightaware appear to have several fedex/UPS feeder flights a day.
Downside is that the services aren’t usually nearly as good.
Hopefully low-speed maglev becomes a thing
https://www.nhtsa.gov/laws-regulations/corporate-average-fue... is the full explanation.
It would be a radically more efficient design than what we currently have, though.
Before we can even think of long-range flights, let's consider mid-range:
A 737-300 has a range of ca. 4000km from 20,000l of fuel. But that's not flying with full tanks all the time. It has a payload capacity of 17t (on top of passengers, I think) and carries up to 149 passengers.
If we cut the payload to 10t and passengers to 100, our "comparable" electric plane has 10t free payload for batteries (3t for the 50 passengers and 7t from the reduced payload). If we, generously, assume that we can add another 10t as "structural batteries" (basically, building the airframe out of batteries, because, why not, but also smaller and lighter engines), we end up with maybe a total capacity of 40t for our batteries (assuming 1kg/l for the jet fuel). We need the energy for a mid-range flight, say 1000km. That would be about 5000l of kerosene, in a 737 (not completely true due to weight loss during the flight). Fortunately, our electric propulsion is probably much more efficient (thermally) than a turbojet, so we might only need about 2/3 of the same energy. That puts us, very roughly, to the equivalent of 3.333l of kerosene, or about 86GJ. Hence our battery would have to offer 3.6MJ/kg.
This is inside the theoretical realm of a zinc-air battery. So with this very rough calculation it does not seem to be impossible to achieve mid-range battery electric flight. And this usually means it is going to happen whenever it is economically sensible.
For long-range flight, though, we would need even better batteries. Like, at least 4 times better. This is not on the horizon, currently.
Even with road vehicles, electric is only viable right now to the weight and load of your average 4-door sedan.
It's not inconceivable that fuel cell electric planes could become a thing as well, especially if these early BEV show other benefits around maintainability, noise reduction, etc. I think its a long shot though, as jet fuel + carbon capture will probably be price competitive before fuel cell airliners become a thing.
TLDR: Long range air travel with batteries is a long time off.
[1] - https://www.youtube.com/watch?v=oZfjyVbcJDI [video]
[2] - https://www.youtube.com/watch?v=aXEyETZU8ag [video]
I somewhat doubt it. The characteristics that make a good battery for a plane make a good battery for a car. I think the only place there's a difference is airlines are likely willing to spend more on batteries.
But they’d be called hydrogen aircraft rather than electric by most people.
However, certification requirements and safety assurance needs will drive both cost and time into realizing fully autonomous aircraft. They will be here, but we are 10-15 years away.
The problem is in how to certify machine learning code. Today, you can't. Existing AMCs (accepted means of compliance) are incompatible with the nature of ML. (The breakdown is specifically with assurance architectures focused on code traceability and coverage.) A new architecture for demonstrating safety assurance with AI/ML is needed, and is being built, but is still 1.5-2 years away from being released, and then it will take another year or two before a CAA (civil aviation authority, like the FAA or EASA) will certify a component with ML code--and that will not be an autonomous pilot. That will come in time, but the industry is conservative--especially on safety-critical matters--and it will take years to develop trust in both technology, human factors, and methodology to work up to autonomously flown passenger aircraft.
From the regulator perspective, EASA has taken poll position in thought leadership. Google their AI Roadmap or their Concept Paper for Level 1 Machine Learning Applications.
There is a small precedent here: the space shuttle flew almost 100% by computers.
There was a small involvement of the pilots when landing and some change of software due to small RAM size in the computers.
I could imagine "Fully-Self-Flying planes" would start out with cargo planes between areas with low population.
Imagine if an airline could generate it's own power and not have to pay a third party for electricity to charge planes.
I don't think it will happen, or at least that it will happen any time soon, but this is one problem that can be solved.
Autoland was developed for and is usually used in poor conditions.
- the power you can get from the charger to the batteries - the power the cells can accept
You can reasonably easily fix the first point with custom infrastructure, so the second point will be the limiting factor, and that one means that it always takes e.g. 20 minutes to charge your batteries, regardless how many you're charging (because with a bigger battery, you're simply charging more cells in parallel, at the same speed per cell).
Gist is going from internal combustion with a ton of supporting or fully necessary tech to fully electric, fully SW-driven, really skeeves me out given the above testimonial and others like it.
I openly allow it's quite possible that airplanes can't fly these days but for software though.
Sure you or your friend may have had a bad experience at that company, but the big players generally won't let software bugs through.
Boeing code leaked in '20 [1] and it was ugly, however it was ~network vs. app layer so unclear how it worked at the engine level.
Add in the track record of CAN bus security difficulties and knowing airplanes use similar tech, "generally won't let bugs through" when paired with the footnoted security leak is a gross overstatement.
[1] https://www.wired.com/story/boeing-787-code-leak-security-fl...
Before you write it off as an overhyped wired article, it was also a presentation at blackhat [2], so vetted by a fairly rigorous CFP.
[2] https://i.blackhat.com/USA-19/Wednesday/us-19-Santamarta-Arm...
Or alternatively, if a plane develops a leak in one of the tanks, it can dump fuel to balance the weight.
Is there a scenario where a plane in flight has its fuel on fire and dumping said fuel helps in any way?
If fuel is dumped high enough, it pretty much evaporates and doesn't fall to the ground. If the plane is low when it dumps fuel, it can hit the ground and bystanders; but, it's not going do much, if any damage. (Assuming it doesn't hit someones barbecue or a smoker.)
Also, Jet-A doesn't burst into flames like gasoline. Even if you soak an area with it, you don't have a firestorm just waiting to blow up.
Cities continue to build new railway stations and lines, usually underground, to improve access to the centre.
But this will free up enormous tracts of land - the railways don't just use land for stations, but the railtrack takes up most of the land (in long strips as it were).
Imagine cities in 50 years, with rail land reclaimed, with Tokyo-like laws that prevent on-street parking (a valuable gift to car owners), freer flowing traffic, more walkable neighbourhoods. There is a lot to unpick.
What you really want to reclaim I feel is roads from cars, we devote insane amounts of land to cars, car parking, and car travel..
The city of Adelaide is an interesting example if you're interested, it's a young city and built an airport 4km from the CBD, which means the CBD can't have tall buildings, the airport has a curfew, noise is a constant hot topic, and it takes up more land than our CBD and most prized suburbs do. It's likely sitting on hundreds of millions worth of real estate, while the train station takes up less than a city block and then the rails weave their way through the rest of suburbia. The most recent Southern Interchange, a car highway interchange, takes up more land than the train station does including it's convergence and junction yard, and all it does is connect two roads together.
The city also tore up all it's rail network when cars took over, and now it can't afford to put the rail back in now that it's proven to be the more sustainable and pragmatic option.
Example: there is a train between Milwaukee and Chicago and it stops at MKE, but it will never stop at O’Hare, because that would be the end of MKE.
Technically you can take the Blue Line from O’Hare to downtown, making dozens of local stops, and then walk a few blocks with your luggage to Union Station, but by the time you get downtown you could be in Milwaukee already on a connecting flight. And those few outdoor blocks are a big deal in winter, dragging soft sided luggage through the slush is not fun.
Side remark: The same holds for roads, of course, with the notable caveat that roads form a flexible network automatically. Planes are just superlinear in their flexibility: If you have n airports and add one more, you get n new connections.
Edit: I'm an idiot and missed that these are 19 seat planes. No, a train that only serves 19 people a day, one way, has a zero percent chance of being profitable, and I doubt it even makes environmental sense if you have to lay 70 miles of track to support it.
(For example, my parents would take a direct bus a similar distance to Heathrow or several other airports. It saves parking costs and driving while tired.)
You'll have to ship the batteries somewhere they can charge/reprocess, but you also need to ship fuel, so it's a 1-to-1 tradeoff (you can ship the batteries by land).
(If you think about it, closed-loop recycling of energy storage is just another form of recharging, but with extra steps.)
One of the big synergies is with renewables: With the right industrial process, you can treat this smelting process as a way to dump excess energy in peak production times.
I think I was drinking too much coffee.
But railway is just another road. In fact i suspect that we will find self-driving cars are too hard to put into the mix with human drivers and pedestrians. So we shall build / cordon off roads and end up with railways without rails.
Fascinated by the adelaide example - thank you
Yes they'll get better, but they might get 10% better over the next 20 years or something like that.
50% improvement in energy density over 10 years would be more conservative than most estimates, which range considerably but none I could find were worse than that:
https://www.google.com/amp/s/thedriven.io/2021/04/28/how-ele...
https://pubs.rsc.org/en/content/articlehtml/2021/ee/d0ee0268...
I read them as saying "transistors have steadily marched toward the theoretical limit in size, batteries will do the same for power"— and that isn't a 10% improvement from where we're sitting now. I couldn't tell you offhand what it is, but it's at least double density.
Also battery prices continue to fall. Some industry analysts still use battery cost estimates from five or 10 years ago for something that will happen in 30 years (battery replacement).
Edit: looks like they’re using extremely high costs for battery replacement, comparable to costs about a decade ago and about 2-4 times current costs for mass produced batteries, let alone 5-20 years from now: “ The cost of replacing such a battery can be projected to reach around $400 to $500 per kWh mid-decade.”
Compare this to estimates/goals by the Department of Energy that say $60-80/kWh is feasible by 2030: https://pv-magazine-usa.com/2020/12/22/doe-offers-an-energy-...
Goes to show if you want to get somewhere, first you have to start. The other top trending thread on making a bit of progress every day comes to mind, it's amazing how far we can get over a long period of constantly making small improvements.
https://www.globalair.com/airport/region.aspx
The chart linked above does not include additives which may be required such as anti-icing/anti-gel.
The energy delivered by the battery in flight, is what you need to use to restore it back to fresh. The more energy you need the better your battery.
Why does it need to be specifically solar? Use electric from the grid, and as the entire grid changes over to other power sources so will this.
The vast majority of grid electricity is still produced from fossil fuels (at least where I live).
Additionally, a “wasteful” process, like electrolysis of water to make hydrogen, can be usefully inserted at onsite wind generation sites for when the grid isn’t requiring/buying vs sitting idle. When you see large wind turbines stopped and you know that there is a constant stream of wind at 50m above that ridge line it’s simply because the grid is not buying atm. I’m positing that aluminum air batteries are viable for aviation for the same reason.
I was looking at taking the Eurostar from London to Amsterdam, and a friend was dismissing it as it took 4 hours where as the flight is ~45 mins. Except its not, the flight its self maybe 45 mins, but you have to get to heathrow (which is further away than St Pancreas) plus get there an hour early. Then we would have to deal with Schiphol and getting to the center of Amsterdam. To me the prospect of spending 4 hours sat down on the train and arriving directly in central Amsterdam, all the while with more space than a plane is much better than the prospect of 4 hours of that.
Now obviously that's a very niche case, and for most people it doesn't make as much sense, but I think people get scared off by the long train times but ignore the extra time needed around the flight.
Many of those are over seas, so an ekranoplane would make sense, if you want to lower the energy output, but a tradition train won’t work for many cases.
Don’t get me started on the distances in Schipol: had too many race to catch tight connections at that airport…
Planes like this will most likely be used for routes from very small local airports to larger regional ones. I'd guess it's more likely to cover things like Rønne - Copenhagen, or Mariehamn - Helsinki.
I feel like we can make fast trains really worth it, but it makes the few connections I mentioned under-supported if you want to remain below a certain carbon footprint.
Can't they fly only over flat surface and very close to the ground?
That makes them quite unpractical in my opinion.
Ekranoplanes use the ground effect, which requires to be close to a flat surface, indeed, but the larger the place, the further you can be. Something the size of a 747 could be a couple dozen meters above the waves and fly smoothly above moderately rough sea.
It’ll take less time to have operational electric passenger flights than it would to build a new high speed rail route. Particularly in the US (Europe is admittedly much better than the US in that regard).
Also, in my experience there are usually more than one train station in larger cities but even smaller ones have them. While airports are only a few even at a country level.