In the course of events in my world (tech = 1920-ish, but no airplanes. Maybe blimps.), a large archipelago nation is invaded by a naval superpower. The archipelago nation, which had been developing aircraft in secret, engages its airforce and wrecks the enemy fleet.

Is this possible? More specifically, is it possible for aircraft to be developed, in secret, to a 1930-ish level of capability? This also includes having trained pilots who are able to pilot these aircraft. No relevant magic is involved.

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    $\begingroup$ Nazi Germany did pretty much exactly this this. $\endgroup$
    Commented Nov 4, 2023 at 6:02
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    $\begingroup$ Since your world dont have airplanes, even if you developed your airforce in the open, people who see them won't even recognize what it is (until they see a takeoff or landing). $\endgroup$
    – Kristian
    Commented Nov 4, 2023 at 6:32
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    $\begingroup$ As the other folks here are suggesting, starting an air force cold takes a LOT of training and infrastructure. Not knowing what sort of story you have going, you still might need to introduce a wild card. A person or book or other inside information who knows all about aero planes and can advise accordingly. $\endgroup$
    – Blaze
    Commented Nov 5, 2023 at 15:17
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    $\begingroup$ @KEY_ABRADE Yeah, well, except everybody knew. Weimar Germany was not allowed to have an airforce due to the clauses of the Versailles Treaty, so they developed a formidable civilian aircraft industry, including suspicious planes like high-maneuverable, ultrafast one-seaters (for racing) and fast heavy-load airliners. $\endgroup$
    – Rekesoft
    Commented Nov 6, 2023 at 12:58
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    $\begingroup$ @Blueriver the real problems are (1) it was really hard to hit a ship from level flight, (2) the bombs would be tiny, and (3) neither dive bombing (4) torpedo bombers existed yet. $\endgroup$
    – RonJohn
    Commented Nov 6, 2023 at 16:50

6 Answers 6


Even in the open, with no secrecy, it would be difficult to develop an airforce capable of destroying an enemy fleet from scratch. No "1930-ish" airforce was capable of it. (Ships in harbor were easier targets, as at Taranto and Pearl Harbor, but ships on the open ocean are much more challenging. 1930s aircraft could hurt a fleet, but not destroy it.) During the 1940s, Allied air forces developed the ability to consistently bring down Japanese fleets but this was a painstaking process involving refinement of every part of the force: planes, munitions, pilots, reconnaissance, communication, fleet command, ground crews, and countless other factors had to come together to make it possible. That's not a development you can really replicate without some hands-on experience of trying, and often failing, to take down ships under real combat conditions.

If you don't have that real-world experience, you can try to simulate it with wargames and training against static targets. However, this would be difficult to engage in secretly because of the scope and size of the exercises. Remember you're not just training pilots to make attack runs - there's a whole process of locating targets, launching and guiding squadrons on the attack, and recovering them afterward that has to be meticulously practiced. Even your ground crew - you can't launch hundreds of sorties rapidly if your crew isn't experienced. You'd need airbases to stage out of, ships to "engage", derelicts to blow up (you'd be amazed how hard it is to make a torpedo bomb that detonates reliably!), the works. Proficiency in these kinds of attacks doesn't just happen, it's a huge job to make it happen. Too huge, I think, to feasibly keep it secret.

And there's a political angle, too: the whole point of an unstoppable airforce is to not be invaded in the first place because of its deterrent value. That's lost if you keep it a secret. Why didn't you tell the world, eh?

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    $\begingroup$ For context on the scale of exercises needed: The British exercises in this period used: 'The Mediterranean sea' as there scope of operations, whilst American exercises often used: 'The ocean between hawaii and the western US'. $\endgroup$ Commented Nov 4, 2023 at 17:46
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    $\begingroup$ The one thing they would have in their favour though, is that if no one else has aircraft, anti-aircraft defences aren't well developed. So secret torpedo bombers and even dive bombers would be able to approach much more easily than in reality $\endgroup$
    – Chris H
    Commented Nov 4, 2023 at 21:51
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    $\begingroup$ The word that stands out in the question to me is archipelago... which immediately reminds me of Oceania and southeast Asian areas... places I'd think would have large areas to practice in without much observation in a period like the 1920s (especially with other nations not having any aircraft) $\endgroup$ Commented Nov 5, 2023 at 6:38
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    $\begingroup$ @ChrisH : indeed, 1920s tech did not have effective anti-air defenses, but aircraft of that tech level did not have the carrying capacity for bombs large enough to seriously hurt battleships. $\endgroup$
    – vsz
    Commented Nov 6, 2023 at 7:46

Consider the secret German rearmament programs of the 1920s.

By the Versailles treaty, Germany was forbidden to develop certain armaments. Russia was another outcast of the international system at the time, and after the Treaty of Rapallo German engineers went to work in the Soviet Union.

  • There was no attempt to hide the fact that aircraft could exist in principle. This cuts both ways, unidentified flying objects cannot be passed as ordinary civilian planes, but agents of enemy nations would not know the telltales of an aviation parts industry.
    ("Interesting, they are building compact, powerful engines. Any indication that they are going into armored fighting vehicles and not just trucks?")
  • The capability of Japanese naval aircraft to drop torpedoes in shallow water came as a surprise to the US, even if it should not have been quite as surprising. Again, intelligence was looking for indications of the things they were familiar with, not sufficiently thinking out of the box.
  • It would probably take several generations of aircraft until they were capable of hurting ships at sea. From the early contraptions of the Wright brothers, over the Short Admiralty Type 81, to something like the Fairey Swordfish, the generations required not just time but also practical experience. Much harder to leap to something like the Swordfish on exercises alone.
    On the plus side, the absence of a known air threat means that ships will not be designed with AA weaponry. Trying to hit an airplane with anti-torpedo-boat guns, ammunition, and training would be challenging. Your fictional naval power might have better anti-torpedo-boat guns on their ships, which might mean bigger and hence slower-firing.

So you would have to have (1) the recognition of the potential of air power, with the decision to keep it secret, (2) a decades-long R&D program, with realistic exercises trying to sink target ships, and (3) a secret production and deployment program. Think of the F-117 stealth fighter. The US managed to bury the program in their defense industry, details were muddled but rumors were there.

You would stretch credibility, but perhaps not break it. Especially if problems and limitations do show up. Say the first operationally deployed squadrons are both limited in number, and unable to hit a defended targets.

During the first battle, a few are hit by the anti-torpedo-boat armament, most get into position to drop their torpedoes, and a few hits are scored. Maybe 100 planes on the attack, 5% aborted or lost at sea, 5% shot down prior to the torpedo drop, 5% shot down after the drop, 5% don't make it home. There are 90 fish in the water. Say a 10% hit rate, and you get 9 torpedo hits for 100 aircraft sent out, a bit over 80 coming home. Those 9 torpedo hits managed to cripple 4 or 5 capital ships. (The pilots were trained to go in close, no torpedoes wasted on something like a destroyer. Also, short-range torpedoes to allow bigger warheads. And the enemy captains were under order to hold formation until the admiral sends 'torpedo boat attack, maneuver independently.' That permission never came.)

In the second battle, the 80 survivors go in, 75% of them are shot down prior to their drop because there are now machine guns on the ship. (Remember, the pilots were trained to go in close to compensate for slow and erratic torpedoes.) The warships have learned to evade more quickly, without orders from the flag, so the 25 torpedoes score 4% hits, i.e. a single one. Which damages but not sinks a cruiser.

The survivors report, the designers design, and in the third battle a new torpedo is deployed, with sufficient range to hit from beyond machine gun range. Also, the aircraft squadrons have learned to attack simultaneously from different directions, so that turning into one group of torpedoes exposes the broadside of the targets to the other.

And so the circle turns.


What are your long-distance surveillance technologies?

L.Dutch has already mentioned one: sound. Sound travels a lot further than the human ear can hear, The first patent for a microphone was in 1877, so by the mid- to late-1920s it's more than possible to set up "listening posts." The technology would be cumbersome and humans must be trained to "filter" out the noise that was uninteresting (wind, waves, commercial traffic...), but it could be done.

If there was a reason to listen that closely.

The second long-distance surveillance technology of the day was telescopes. The 100" Hooker telescope on Mt. Winston was the largest in the world from 1917. That's a big honking telescope, and while used to view the stars, there's nothing to say (other than it would be whomping impractical to use) that it couldn't be leveled at your target civilization to watch closely what they were doing. You could see a lot with a 100" telescope from almost any distance so long as planetary curvature and intervening geography permitted it.

If there was a reason to look that closely.

Your best friend is working where you can't be seen or heard

Knowing nothing about your planet, let's assume that there's a side to the archipelago that faces the invading nation and the other side that faces open sea to the horizon. Bully! You can operate your test programs on the sea-side of the archipelago almost with impunity. Caution is always required.

Movement between the islands could be done by flying your craft in twilight hours, taking advantage of the heightened "optical noise" of the sea surface to hide your craft from prying eyes and keeping the sound of any engines as near to the surface as possible to mix it with the "auditory noise." It's not a guarantee of not being seen, but it would go a long way toward it. Your people might even master night flying — but that's more of a stretch. Night flying in the days without radar on the planes was very, very difficult, especially for navigation.

Which means your biggest problem, as usual, is espionage

Everything I've said describes what you could do to hide your project from casual observers at a distance and what those observers could do to overcome those limitations if their attention were drawn to the island. What I've described is unusually extreme. There's no historical analog that I'm aware of that reflects the level of effort I've described. Which means you need to be sure not to give anyone a reason to be extreme.

A healthy counter-espionage program is a necessity to make sure even a rumor of your program stays inside your borders. It's beyond the scope of Stack Exchange to describe such a program in any detail... but I'm sure spies will be involved.


Yes, it's possible. Given clever use of geography, chronology, planning, and paranoia... it could be rationalized.


To develop an air force in secret you need to keep the information away from those for which it has to be a secret.

Considering that planes flying around will be seen/heard, you would need something like the Area 51 base, in the middle of a remote area, with strong security around it, to really be secretive. Even better if you had something like bases in the steppe, like USSR did. The more remote, the better.

But that is going to be pretty difficult on an archipelago nation. And the more effort you put into preventing people from seeing/accessing the base surrounding, the more the curiosity of interested agents will be tickled.

However difficult doesn't mean impossible.

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    $\begingroup$ One could do lots of training based on Midway and the rest of Hawaii would never know. $\endgroup$
    – Jon Custer
    Commented Nov 4, 2023 at 15:02
  • $\begingroup$ @JonCuster True, but you're shipping an awful lot of fuel, plus spares and training munitions to Midway. The downside of an archipelago is that there is only a limited number of placed that need to be checked if a huge amount of supplies is suddenly being send, even if you can't find out where. And with 1920's tech sans airplanes, the hostile nation probably has subs to have a look at Midway, if the island is too uninhabited to sneak in a spy. $\endgroup$ Commented Nov 6, 2023 at 13:47

Yes and No.

This line:

"tech = 1920-ish, but no airplanes. Maybe blimps."

Makes me say 'No'.

A lot of answerers have quite rightly pointed to pre-WW2 Germany and how they trained an airforce in secret - however, they have omitted one key point - the reason Germany was able to do this was due to the extensive German gliding Clubs that existed from the 1920s onwards.

This ensured that there was an extensive knowledgebase of aviation understanding and piloting skill.

In the 1920s, heavier than air flight was already well established and understood and so a Gliding program wouldn't (and didn't) raise any eyebrows.

So - if heavier-than-air flight is unknown in your world building scenario - we have a pretty big hurdle to get over. We can't have a cadre of trained/skilled pilots. Unlike Germany, we don't have a population base with all of the transferrable skills needed to pilot a powered aircraft.

And the problem here is that the skills required to pilot an Aircraft (or simply navigate in 3D space) are pretty unique. If we look at other secret projects in history (say the various exploits of the Skunkworks) - there's a significant amount of overlap from ordinary aviation - meaning that the development of the niche/specialist skills represents a small fraction of the overall skills needed - The SR71 had the challenge of getting your head around the speeds being travelled at (you've never been lost until you've been lost at Mach3) - but that's merely an enhancement to the existing skill of navigating an Aircraft.

The development of Heavier-Than-Air flight is such a groundbreaking achievement that I doubt it would be possible to be kept secret.


1920s Ships - the amount of AA Firepower they wielded could be summed up as 'Non-existent to Pitiful':

Ma Deuce didn't really exist in the 1920s - and wasn't widely adopted until the 1930s.
Oerlikons didn't exist in the 1920s.
Dual-Purpose 5-inch/38-caliber gun didn't exist in the 1920s
The Bofors gun didn't exist in the 1920s.
And perhaps most importantly of all...

Proximity fused Projectiles didn't exist in the 1920s either.

Now - to be fair - all of the above (except the proximity fused munitions) came into being in the mid-1930s. What you see a lot of in WW2 is that various ships that initially had little to no Anti-Aircraft armament got retrofitted in the late 1930s or after the likes of Pearl Harbour to get a significant upgrade to their anti-air capability.

Also - to be fair - the threat level of 1920s era aircraft is likewise miniscule - they are almost exclusively biplanes (insert Fairy Swordfish British Meme) with very limited bombing capacity...

But we have to take a pause here and talk about the 1921 American Airpower test - where TL;DR - a number of ships were attacked by Aircraft in a trial - the initial payloads of WW1 size bombs (100Kg, 600 Pounds sizes) proved to be ineffective - but Billy Mitchell (absolute legend) arranged for 1000 and 2000 pound bombs to be dropped - and with 3 near hits under the waterline to a captured German Battleship - they were able to sink said Battleship (although this test was highly controversial for a number of reasons - the Navy asserting that a well-trained Damage Control party would have prevented the sinking).

However - we must consider that the above test took place after the advancements in air-power that were driven by WW1.

I will add a little aside here - In WW2 - most of the anti-ship dive bombers ended up using old Battleship calibre Armour Piercing Shells (12 inch, 14 inch etc.) with some modifications to turn them into bombs. Whilst this was done in WW2, so 1940s tech, the actual munitions used were older variants of Battleship shell - Essentially all those pre-Treaty (The washington Naval treaty - I think 1926?) Calibre shells. Since the shells exist in the 1920s - I'm allowing it.

To Conclude

From a pure 1920s technology perspective - most of any naval Superpowers ships are going to have very limited Anti-Aircraft firepower. It is possible, with 1920s Technology to successfully sink a Capital ship. That said, most of this innovation came about from the results of WW1. Furthermore - the most effective Anti-Ship weapon (Modified Battleship AP shells converted to Bombs) sort-of existed. However - without a means of training pilots or at least having a segment of the population with enough transferable skills to be able to do this all in secret is a big stretch.

My suggestion:

Have gliders exist in your story, but make powered flight unknown - this allows you to solve the problem of having Pilots. You could also introduce a sport whereby Glider pilots practice dropping things from their cockpit, to see who can get it closest to a target.

Now you've got the skills, you've got aerodynamic understanding - your countries key advantage is making an Aero Engine (light and powerful enough) - you could still keep this secret as you could have the planes cut the engines when coming into land.

  • $\begingroup$ How would they have an extensive glider programme without powered aircraft to act as tugs to actually get them into the sky in the first place? It could be done with balloons I guess, but not very practical at scale. $\endgroup$ Commented Nov 5, 2023 at 1:13
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    $\begingroup$ @MichaelMacAskill - Pushed off the edge of a cliff, Winch Launched, Downhill + SkiJump etc. $\endgroup$ Commented Nov 5, 2023 at 1:32
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    $\begingroup$ Gliders effectively fall from their launch height, at whatever their glide ratio is, unless catching a thermal. All of those launch methods give a minimal initial altitude and hence minimal airborne time per flight. This is not a practical way to train pilots at scale, and at the sorts of manoeuvres the OP needs them to develop skills at (rather than just maintain control and then immediately land). Pre-war Germany had the advantage of powered tugs for its large glider programme. $\endgroup$ Commented Nov 5, 2023 at 1:51
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    $\begingroup$ @MichaelMacAskill - I partially agree - however if the choice is between: No piloting experience at all and some piloting experience with Gliding - then the answer is clear. Since it's WorldBuilding - maybe the location has a number of properties that make it uniquely suited to generating strong thermals? $\endgroup$ Commented Nov 5, 2023 at 1:58
  • $\begingroup$ Indeed, the OP could convincingly tweak this to work in their world. Maybe I was being too constrained by the historical situation in this one. $\endgroup$ Commented Nov 5, 2023 at 2:06

Just focusing on "build it in total secrecy" part, that could be tricky if the opponent isn't so reckless as the invade without any meaningfull scouting prior to the invasion.

An archipelago is both a blessing and a curse. On the plus side, you probably could base your airbases, and perhaps even the production facilities, on a remote uninhabited island. That limits the risk of spies visiting your population centers seeing strange flying machines.

The downside is, there is a small and (assuming our 1920's knowledge) known list of islands the enemy would have to check once they notice the large and inexplicable resource shipments you're sending around. It seems unlikely that an island with access to all construction and fuel resources, and enough space to put the whole supporting infrastructure, would have remained uninhabitted for so long. And even then, you'd have to send a large number of workers to these facilities, which can also be relatively easy for spies to find out.

And a 1920's era navy probably has submarines that can have a discrete look around various islands prior to the invasion. I find it probable that one of those subs will spot some airborne planes. Other anwers already mentioned the large amounts of exercises neccesary to develop not just the planes, but the technique and doctrine to threaten a navy at sea. So there'll be a lot of flights from and to your training airbases, any one of which can be spotted. The airforce might be able to spot the enemy scouts in turn, but they probably won't sink them outright if there is no war yet. And even if they do, recon assets vanishing in a certain area is a very clear indication that there is something dangerous to your navy in that area.

Bottom line, if the enemy isn't suicidally overconfident or inept at scouting, they should be able to find out that your nation has new technology that lets their warmachines fly.


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