I mean the age of air transport with commercial jet.
My idea is that passengers trains and cruise ships remain the main means of transport until mid 70s at least.
So it looks like what you are getting at is to avoid commercial passenger aviation as such, regardless of the nature of the power plant.
Infact i have said "the main",not the one.
Of course great planes as Supercostellation or big sea Clippers can be part of this scenario.
....This can be right for United States,but not for Europe.
50s and early 60s was a great time for ocean liners (the last hurrah).
And passengers trains rules until late 60s almost.
The thing is, even if jet propulsion remains completely uninvented, the high speed it offers--ten times the speed of a practical surface ship, at least on the scale of an ocean liner, can reasonably attain--is very attractive. It has its drawbacks of course--"jet lag" is a thing, as is the lack of the luxury of ample space to walk around and do diverting things. But getting across the ocean in just one day is something of great value to many potential paying passengers. The idle rich can afford to dawdle, and ordinary persons making a crossing for some very essential purpose can take half a week or more out of their lives--provided they only do it once or twice. The market for ocean passengers, even if it is the only game in town, is inherently limited by the number of people who have the
time to spare. Divide that further by the number of people who can afford to buy a ticket and you can see that by offering much faster travel, despite the inconveniences, the market for air travelers is much larger. The majority of modern industrial nation's populaces are in families headed by a working person (nowadays, most often two of them) who rarely get time off in blocks larger than a week--maybe two weeks. For an American family in the 1950s-70s period you are talking about to be able to afford a European vacation and to be forced to get there and back on a ship that takes 3 days each way, they'd have to spend half their time on the ship itself, with only 8 days for Europe itself. Two full weeks off is pretty luxurious to count on having. If they have the alternative of taking a plane that can make they crossing in just half a day, even allowing another day at each end to cross the USA to an Atlantic coast city with direct flights to London or Paris, they have at least two more days in Europe, and in truth they ought to be able to get two more by doing all the traveling in just one day each way.
So if the commercial passenger planes exist at all, one can expect they will rapidly eclipse the ships. To business travelers, time is money. To vacationers, time at the destination is worth more than time merely getting there.
Now of course sea travel is inherently cheaper than flight; the portion of the cost of an individual ticket that goes to maintaining an aircraft and fueling it, and even the original cost of buying it, is going to be larger than the portion of a ship ticket, one would think. But wait--given that a sea voyage takes days, a pretty comprehensive suite of services has to be offered each passenger. They need a place to sleep, as well as meals and lavatories and baths. One can demand an air passenger sit in single seat for a long time, maybe as much as 24 hours, but at some point it has to be possible for people to get up and walk around. The ship then must devote a lot more mass to each passenger, even in steerage conditions.
More to the point, the cost of operating an aircraft or ship is divided by the number of passengers it can deliver--revenue passenger miles. An airplane is smaller than a liner, even today with our really big jets and much more so in say 1946. But even in 1946 it could go so much faster, that it could cross the Atlantic in ten round trips while the ship makes just one. So the aircraft travels ten times as far. Many costs are proportional to distance covered of course but not all are; the latter are much cheaper for each air passenger even if the price is inherently higher for an airplane.
The plane ticket can thus easily cost as little as a ship ticket; while ships remain the more common mode the price won't come down (much--the ship ticket buys hotel and dining for all the extra days so the plane ticket needs to be discounted to allow the traveler budget for meeting those needs at the destination) as long as ship costs remain the benchmark. But once it comes down to that level, potential passengers will line up at the airline ticket counters hoping for a seat; the demand for more and more aircraft will skyrocket while the ships must sail half-empty or be mothballed to shrink the capacity to the falling demand. When air travel becomes dominant and capacity grows to cover the old demand for ship berths, it will continue to grow as the number of potential passengers rises due to the quicker transit times allowing people to consider long distance travel in little chunks of time. And then it will grow further because when that market is saturated at the old sea ticket (minus unneeded accommodation fees) prices, the price for discount, less comfortable but equally fast tickets will start to come down further to drive the cost down to match the actual costs of transporting a customer a given distance. The total number of passengers the industry carries per year will swell far beyond what ships could have expected; the percentage of the population of a developed nation that makes a given number of trips per year will rise. This generation's answer to the immigrants of 1900 who made a single crossing in their lives will be very poor people from the Third World who nevertheless can afford, not just to travel to a rich metropolitan First World nation once to seek their fortunes, but then even if they remain quite poor by their host country's standards can afford not only to send generous remittances to their family in their home country, but to travel back to visit, not once or twice but dozens of times in their lives. The idle rich who once spent a good part of their ample time lounging around in the floating palaces of first class ship accommodations now instead pay two or three times what they strictly must to enjoy much smaller (but still quite comfortable) first class thrones with many flight attendants and get where they are going very much sooner; they just go more places on quick whims, jetting all around the world instead of having to choose carefully where they will spend months. The businessmen in the middle business class might indeed spend more time out of their lives on planes and airports than their middle-class ancestors did on ships, but this is because they have the ability to have a literally global footprint, able to be anywhere in the world in well under 24 hours--and back in their home offices before the week is out, having conducted half a week's solid business far overseas.
Now with jets, all this is faster, cheaper and on a bigger scale than if some strange turn of history or ASB intervention restricted the planes to piston engines and propellers, but the basic trend is so strong that it looks to me that to have ocean liners still dominate the trade in 1970, let alone 1980, you need to somehow abolish the passenger airplane as such, in toto. Just banning the jet engines will not serve your purpose; the liners are still going to be mothballed even if the best airplane remains a Lockheed Constellation.
So,if you shot the damned Hitler in WW-I or send him under a taxi in early 20s (Weimar Republic in some way survive..and so) and avoid WW-II is reasonable to think that the jet age is delayed by some decades (we said..80s?)
This seems the main solution.
Un, no, absolutely not.
Jet engines is a thing jetliners another.
And without WW-II great airports around the world are less widespread
I not want avoid the jet age at all,i want delay it more that possible.
So,without WW-II and with jet engines introduced in mid 50s is presumably that the jet age become in very late 60s-early 70s.
Note that in a timeline without WW-II we not have neither the cold war (or not the same that in OTL).
Riggerrob below opens with a statement that seems to amplify your point...
Without WW2, the RAF and USAAF would be without most of their long-range experience, even worse would be fewer trained aircrew to fly long-haul missions.
Indeed, WWII created a vast investment in air fields that (for heavy high-powered piston planes) were paved and lengthened too--this was essential for jets, especially early jets. Modern turbofan engined planes can operate from remarkably rough fields, especially when designed by Soviet or nowadays Ukrainian firms like Antonov; early jets were rather anemic on takeoff thrust and needed pretty good runways. Add to this the literal legions of USAAF/USAF/USN/MC and RAF/FAA trained pilots and aircrew forced to learn their art in rough conditions and you have quite an ample, indeed oversaturated, pool for airlines to recruit from. Take away the war, which I agree would also limit the scale of the "Cold War" considerably, and instead the industry must invest out of private funds in each airfield and train up its crews as needed, and these crews, each pioneers in their arts, will make mistakes that will only slowly teach by trial and error the best practices of long-range (or short-range for that matter) commercial aviation.
But...
Also consider that (even with the war) piston engine technology peaked around 1950. Even after the war, Engine manufacturers still needed a few years to work the bugs out of their best war-time piston engines....Then they needed many more years to perfect turbo-chargers or super-chargers. Turbo-chargers needed exotic, high-temperature metals as sophisticated as the metals used in jet engines.....
Wright's Turbo-Compound engines might have been the most fuel-efficient, but Wright took several years to de-bug them. For the first few years, Lockheed Constellations had the reputation as "the best 3-engined airplane flying the North Atlantic route."...
Now this seems also to suggest that even if the potentials of much faster ocean crossings (and I haven't even mentioned how airplanes fast enough to safely cross oceans also eclipse the hitherto quite rapid passenger railways and steal market hence development budget from them too) are as compelling as I think they evidently are, still there might be a long delay, thanks to the dang piston engines being such a pain. (They were also quite noisy--passengers flocked to the Vickers Viscount powered by turboprops because it was very notably quieter--the stress of enduring loud piston engines was a significant drawback of even the best piston planes. So they were a pain literally as well as logistically!)
However--note the passage I bolded. The compound engines of postwar derived a good percentage of their shaft horsepower from their superchargers. If no visionaries such as Whittle or Ohain were ever born, nor the dreamers at Lockheed who took to designing jet fighters before they knew of a functional turbojet engine physically existing, the evolution of the supercharger alone provides a path for the development of the turbine engine.
But in fact, such progressives as the actual OTL inventors did exist; Lockheed designers were that confident the turbojet was around the corner; Soviet designers were hard at work on it as well. The turbojet was much desired, because the propeller imposed inherent limits on attainable airspeed, and airspeed was wanted for many purposes.
I think killing off damned Hitler is a capital idea and would argue that without him personally, Europe stood a good chance to get through the 1930s and indeed right up to the present day with no great wars and with small wars in the Balkans perhaps severely limited in scope and duration, more like the brief flare-ups of violence that have been typical of Latin America in the past century. Mussolini I think would have backed down from any severe confrontation; Stalin was the Great Procrastinator, because while ideology and ambition alike (as well as prudential mere defense considerations) drove him to develop mighty armies, putting someone competent to command those armies on the long-delayed liberation of Europe's proletarians would create a potential rival to himself. Hence the cycle of build-up and purge. He'd always be waiting for the right moment, for the ideal "correlation of forces" in Leninist jargon, and it would never ever come. Perhaps in such an ATL some successor of his, with the Bolshevik ruling clique never burned and chastised by the terrible cost of the Great Patriotic War, might be bolder, but I think the collegial mode of rule at the top would reassert itself, some clique on the Politburo would check the more aggressive clique, and the Soviet policy of heavy defense and caution would prevail. With the capitalist powers never coming to blows, there would be no safe openings to exploit. The mere presence of a heavily armed Red Army (of uncertain, unproved and no doubt inferior to OTL qualities to be sure) would be enough to keep arms levels pretty high, though low by OTL standards and probably quite backward too.
But does this mean technological stagnation in general? I would argue, no. The lack of centralized hothouse development would be offset by the lack of wholesale destruction and mistakes made in haste. Overall I think just about any technology you can name would proceed steadily, acquiring funding on the basis of immediate merit.
Would commercial aviation however take a disproportionate hit? You and riggerrob have made a fair case for it, but I think you underestimate the demand that was felt. Without such fantastic feats of engineering and aerodynamic elegance as the Spitfire or Mustang or even Mosquito to claim public technophile admiration, you can bet the advancing art of passenger planes would take on that future-craving gaze. The desire to get there sooner would be multiplied by the prestige of flying state of the art. Airlines would be keen for newer, faster, sleeker aircraft to upstage their rivals.
As fast as possible did not economically pay the very best of course. In the American market, Lockheed led the way with the fastest, most aerodynamic designs, but their carrying capacity lagged the more stolid Douglas DC-3, and it was the Gooney Bird (a WWII name, not to be applied in such an ATL) that made American air lines inherently profitable even before the air mail fees that hitherto had spelled the difference between operating in the black rather than the red. All the airlines of the interwar period--until the DC-3 came along--required some sort of government subsidy. But that subsidy was generally forthcoming one way or another, because both nationalists and captains of industry recognized the importance of staying near the cutting edge of aeronautics.
The turbojet was applied first to fighter designs OTL, because its day happened to dawn around the time of the great war. But I don't think it follows from that that only if an urgent need was felt for expensive ultra-fast fighters and attack planes that the engine would have got funding. Other posters have pointed out how Whittle was able to trudge along, far more marginally than he liked to be sure, on mere private backing. The Lockheed designers surely would have moved to get their company to back the development of such an engine had it not been dropped in their laps first by a desperate Tizard mission. The Soviet designers were dependent on no foreigners for their progress and there is every reason to think they'd have a useful version working well before 1950 (there probably to indeed be installed in a fighter first, but with plans to move on to other categories of aviation soon as well). I suppose Ohain might have been worst off relative to OTL in such a situation, for without someone to challenge the Versailles restrictions Germany was forbidden to have any aviation industry whatsoever. Before Hitler, this was evaded by moving operations out of the country, to places like the Baltic states or in cooperation with Fokker in the Netherlands--indeed for a long period, German weapons designers operated on Soviet soil! I'd think even Ohain would have found backers and found himself in one of these overseas locations, perhaps there to pre-empt Whittle.
Why was the turbojet so desired? It offered liberation from the inherent limitations of the propeller; even if it seemed in early days to be doomed to inefficiency, the substantially higher speeds to be reached even in the strictly subsonic range would permit operation at higher altitudes. Speed was worth quite a lot in commercial aviation; the time it buys reduces the period in which something mechanical or structural might fail (offset to be sure by operating in more stringent conditions, but the unforeseen shortcomings might be addressed with redesign, leading to enjoyment of inherent advantage). The propeller has some virtues, but propeller tips were already hitting the speed of sound, with unfortunate results, as early as the first World War! The industry would be keenly interested in a power plant that did require it.
So, with early lab-bench functional turbojets in hand on a shoestring budget, I think even a peaceable Atlantic world would produce keen investors to work out bugs and develop them to be reliable and powerful and efficient enough to install on large airframes suitable for carrying passengers, at least by the dozens if not the half-thousands (initially!) The goal would be to cut travel times, and by doing so bring markets formerly completely out of range into play. Such as the transAtlantic.
Note that in the USA, air lines, once the DC-3 and comparable rivals were in play, were profitable businesses even in the middle of the Great Depression. Had the great American aero firms not had large military procurement contracts to rely on, they still had a decent income from which to make investments. I am less sure of a hypothetical ATL situation overseas, but to the Soviets market conditions were irrelevant; Britain and France might possibly provide government subsidies with any eye to the military revolution reliable turbojets (and with them turboprops, and eventually turbofans) would imply.
The Japanese appear surprisingly high on the lists of innovators and pioneers of some fields in this period, such as nuclear science--but I've never heard of their doing much work on turbine engines. Still, unlike the Europeans at peace, they and their Chinese enemies certainly would form a market for highly advanced war planes! The Chinese could not afford much and OTL got second-hand goods, but would a world with Europe unstressed by the threat of serious war (beyond prudential shoring up the Eastern European buffer states against conceivable Soviet aggression, and "damned things in the Balkans") ignore the east Asian war as they did OTL? Perhaps here the USA would not be the only interfering power. If Britain kept to their old alliance with Japan it would annoy American interests, but if she played a mediating role in damping down the conflict (in Japan's favor to be sure) I can't see Uncle Sam coming to blows over it. I can see a situation where the British are marketing some expensive new warplane designs to Japan while the Americans retaliate by effectively donating some to the Chinese, making it a sort of inter-superpower proxy war. So both Japan and China's involvement in the turbo-engine scene, if only as purchasers, might be jump-started. (The Japanese, I am sure, would turn pretty soon to their own designs, if only they could get the resources--a situation where British good offices damp down the war and secure channels of world trade open for Japan would allow them to do so, if only on a shoestring).
Meanwhile, sooner or later, and I predict sooner, a suitably practical turbojet or possibly turboprop--perhaps even a turbofan of some kind at the very beginning of commercial service--would be devised and fitted to a suitable airframe, and offered for sale as a passenger vehicle.
How soon? Well consider
this OTL example! It was ready to market in 1950, at the same time as the more famous Comet that beat it to first test flight by a matter of weeks. Perhaps had this design (not made in any of the first-rank nations, even, although of course the aim would have been to tap into the US market) overcome the hurdles it faced OTL (note that it was killed in favor of concentrating on developing the CF-101 "Canuck" fighter/interceptor--which had an illustrious history OTL, being NATO's only all weather day/night fighter for quite some time--but illustrates the dark side of war-footing funding on general progress as well) it may have proven more durable and reliable than the Comet. Maybe not; its pilots on its maiden flight to New York refused to fly it back because of alarming noises from the wing-but that problem was diagnosed and solved. Meanwhile it got to NY in record time and made quite an impression--a decade before anyone but DeHavilland had anything like it to offer! (The next passenger jet to go into service was a Soviet one, a revamping of a bomber design).
Now of course during the war years and in the half-decade afterward, improvement of turbine engines got a whole lot of investment, and the degree of maintenance Cold War mobilized Air Forces could apply to war planes far exceeded what was cost-effective for air lines. Without the heavy funding of dozens of jet designs to be procured by the hundreds if not thousands, would it have taken longer than to 1950 to get the sort of engines the Avro Canada Jetliner could rely on? Perhaps, perhaps not. What if a less efficient but thereby more durable turbojet core had been driving a turbofan to raise the thrust and thus offset the poor efficiency of the core?
OTL once turbine driven aircraft were offered to customers, the passengers flocked to them, because they were quieter (for the passengers anyway, if not bystanders near airports!) as well as faster. And futuristic of course! The turboprop trumped the piston engine, then the turbojet was preferred over turboprop, then the turbofan meant both still more quieting with substantial fuel savings.
The airlines drew an additional benefit--turbine engines, although they do require very high-tech materials operating at very demanding conditions, still are fundamentally much simpler machines than piston engines, and this is reflected both in less frequent requirements for overhauls, and faster, cheaper overhauls when the day for them comes. This means that while piston engined planes spent a good portion of their working lifespans in hangars being maintained, a comparable plane driven by a turbine engine would spend less time per year there, with the difference being revenue-earning time. Airlines that jumped the gun and adopted turbine engines early might regret it if the design suffered from too many pioneering features not fully debugged like the the Comet, but when the "Jet Age" proper you wish to "delay more than possible" (whatever that means?) did arrive, they were more likely to regret delaying too long, or perhaps buying a more tried and true turboprop when a turbojet would have been available--this was the more common error that had to be quickly made up by a swift if somewhat backward jump onto the new bandwagon! The economic savings of lowered maintenance costs per air mile in combination with the objective fact of much more rapid travel plus subjective reduced discomfort due to lower noise for passengers which expanded the market made the jet age come in fast and decisively once suitable planes were available.
In a world with no great wars after 1918, I'd think that the air lines and the aeronautical manufacturers would anticipate all this if somewhat dimly, and invest heavily from a world economy that did not suffer the devastation of the second Great War quite enough to bring the engines on line, if not by 1950 then anyway no later than 1960.
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In order to keep your ocean liners dominant, I think you need to eliminate the passenger air business completely, or at the very least come up with some offsetting factor that keeps it marginal despite the inherent advantage of fast travel. Given the basic laws of physics OTL, there is no barrier that can be expected to hold up the exciting and glamorous development of aircraft pretty much along OTL lines for long; if military budgets are a tiny fraction of OTL, civil investment funds would still be forthcoming. The cost of creating huge airports and the lack of the surplus of well-trained flight crews of OTL will slow things down a bit, but I don't see them stopping it--if necessary the air fields will be built piecemeal, the crews trained up as needed. The latter might result in more accidents and deaths, but note that that has rarely held up the progress of aeronautics much. Even after the loss of the
Hindenburg, agents for the Zeppelin passenger line now deprived of any operational craft (the
Graf Zeppelin being grounded) were besieged with inquires when would Zeppelin make a replacement, so they could plan their own trips on the new airship. Just about every major, important aircraft design ever made suffered crashes of prototypes that were generally fatal and just about always involved the total loss of the airplane. (Note that the Avro Canada Jetliner only ever had one airframe completed--and that one suffered a crash in testing--but was repaired successfully and the crash didn't kill anyone. I suspect it was a very good design indeed and bitterly regret it didn't enter service). Once approved for service, a survey of crash statistics will show that even new models that over their lifetimes prove to have remarkable safety records have a spate of crashes early on--the bugs have to be worked out and flight crews have to learn the quirks of a new type. Yet people generally fly on airliners without worrying too much.
Nor should they; overall air transport is a lot safer than risks we take every day on the road in automobiles. But people aren't very rationally calculating about risks.
You might want to do an ASB reconstruction of basic physics to make HTA aircraft impossible. I'd predict that in that case, however, unless your ukase can stretch to make balloons impossible as well or somehow make both propellers and jet engines ineffective, you'd just shift things over to an unending Golden Age of airships instead. OTL it is hard to find a niche for more than the handfuls of advertising blimps we have, due to the high capabilities of airplanes and helicopters, but if you can ban the latter but not the former, while airships probably can't compete with railways for travel over continents with well-developed infrastructure, they will still be quite superior to waterborne ships in the matter of speed--not ten or twenty times as fast to be sure, but at least twice as fast. Airships are not very suitable to be pushed to the fantastic speeds we expect of airplanes, probably they should never be designed to go much faster than 60-70 knots. But vice versa at those speeds they have excellent fuel economy compared to any airplane; they can cut across land barriers and shallows waterborne ships must detour around; they can be useful in the interiors of poorly developed land masses such as the Canadian far north or Siberia, or for tht matter the Sahara or Australian outback. (They are not so great for crossing high mountain barriers, but if they are the only aeronautical game in town they can be optimized for that too, and thus serve well over terrain that is very difficult to drive an efficiently straight road through, thus perhaps snatching some market from the railroads after all). Over the oceans, they would operate in more directly comparable competition with ocean liners, offering in miniature and lightweight form the same luxuries the ships do, but still cutting substantial travel time off the voyages, so I predict that in such an ATL, long-range airships, collecting all the enthusiasm and funding that airplanes mostly got OTL, would be operational by 1920, reach a plateau of basic capabilities by 1940, and after that enjoy incremental improvements in lighter, more suitable materials and clever design features that would make them workhorses nearly on a scale to OTL modern HTA aviation--indeed, considering their much slower speeds trapping more people in transit, the overall world air travel market would be smaller but the fact that more aircraft would be needed to convey a given number in a given time might mean more airships in operation than we currently have passenger jets!
Well, if you can ASB forbid airplanes as such, you can do so with airships too. I think what you want to focus on is what sort of passenger ocean liners would we have by now and how many of them.
I can suggest another ASB maneuver that might be less daunting and arbitrary than just pretending aircraft are impossible. Suppose, getting back to the irrationality of human choices regarding risk, people were just plain terrified of the idea of flight? That being separated from the ground with no visible means of support brought on paralyzing panic (and possibly heart attacks) that only a tiny minority of our species could master or overcome--or still more rarely, did not suffer from. The degree and ubiquity of the panic can be subject to negotiation--at one extreme, anyone who talked seriously about trying to develop balloons or gliders would be judged dangerously insane and locked up for their own safety, and we would have no aeronautics whatsoever. At a lighter degree of affliction, there might be some retarded development of aircraft of various kinds with lunatic daredevils undertaking to fly them--but at any rate no businessman, not even one himself among the happy few daring aviators, would take seriously any scheme to try to sell seats on an airplane (or airship!) to a paying public. Some would come forth, but not nearly enough to make it profitable. So, perhaps the state of the art is only moderately retarded as the militaries of the warring and rival nations vie to put their own ace lunatics into aircraft that can defeat their enemy's lunatics in air combat, and perhaps bomb them--but never thinking they can put ordinary draftee grunts into a transport plane without facing full-on mutiny! Any involvement with flight might have a cachet of romantic heroism to make aviation's romance of OTL pale in comparison, but then again everyone would know these folks are just plain nuts.
In these circumstances, you can bet people will stick to roads, railroads, and nice waterborne ships, never mind any scientific analysis of the relative risks or costs involved.
I don't suppose this paralyzing fear of flight would have any great impact on the evolution and history of the human species up to the times when the prospect of actually achieving flight seems to be in grasp. Some Chinese stories we've heard of might never be told and the possible basis behind them never be attempted. (Or the Emperor has the maniacs involved executed for quite different reasons than the supposedly wise emperor in Ray Bradbury's rather reactionary little story I had in junior high literature). It might have some bearing on mythology I guess. Perhaps Christian (or Islamic) angels do not have wings, they just appear suddenly out of nowhere, but standing firmly on the ground. Or the fact that they have wings and are seen to fly is one of the differences between an angel and a human--we never wish we had the wings of an angel, unless we also wish we had their courage or fearlessness or security too. But otherwise, except for myths, paintings, and the sketches of Leonardo da Vinci, things go as OTL. (Perhaps Leonardo was one of the few lunatics unafraid of flight?)
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This is what you need--people terrified to fly, I think. Otherwise all logic will sideline the ocean liners as soon as it becomes technically feasible to fly over the seas at a reasonable price with reasonable safety, and it does not matter whether technology progresses in a fit of frenzy between periods of exhaustion or steadily in a world that has found peace. Among OTL humans the desire for flight, as well as the pragmatic benefits it brings us, are both strong enough that nothing will stand in the way short of 1) it being impossible or 2) our civilization being utterly destroyed, or so devastated that we are retarded by centuries and remain that way for centuries.
Or 3), people are not as they are OTL, and the desire to fly is replaced by terror at the idea and refusal to consider it as an option.
Even if you are willing to grant an auxiliary role for prop planes in a minor second place, you would have to adopt a mild form of this--enough fear to dissuade a majority, while a daring minority form a niche market. Even then, the fearful majority would be jealous of the ability of the less fearful to zip about the globe while they must plod, and possibly therefore set up artificial barriers, and prohibitions for the good of public safety and order.
A dose of ASB insanity of some degree is required I think.