A large group of billionaires, engineers, pilots, and volunteers come together to announce the creation of an aircraft-based civilization. Here, people spend most of their lives aboard an aircraft, whether it's an airplane, seaplane, helicopter, gyrocopter, cyclocopter, hot-air balloon, or airship. For them, spending time on the ground or at sea is as rare as spending time in the air is for us.

The group tries to get its society recognized as a nation, but it inevitably runs into problems with airspace violations. The team has a few options...

  • Limit operations to international airspace.
  • Engineer your aircraft to fly as high as possible, and hope that Earth's nations don't mind.
  • Ram through a massive reform in international law that significantly drops airspace boundaries. The upper limit of modern airspace is vague, but it's often set to the Karman line and that won't cut it.

Economically, there isn't anything of value in the air. The new civilization will be extremely reliant on imports, but it has to find a way to pay for all of that. Perhaps people can make money by transporting cargo, conducting research, and serving as aerial mercenaries. I get the feeling that this won't nearly be enough, though. It's a longshot, but maybe the country can apply for international aid.

Also, I don't think it's ideal for their aircraft to have to land in a foreign airport every few hours. For this to work, there needs to be an airport in the sky, perhaps made up of a fleet of airships. This is where the engineers come in. There's a Wikipedia article on airborne aircraft carriers, but apparently one of these has not existed anywhere in the world since 1935. Besides that, there's the problem of landing an airship on an airship. How feasible is it to build a flying airport today?

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    $\begingroup$ Welcome to WorldBuilding, StarlightDown! If you have a moment please take the tour and visit the help center to learn more about the site. You may also find Worldbuilding Meta and The Sandbox (both of which require 5 rep to post on) useful. Have fun! $\endgroup$ Jun 10, 2018 at 21:54
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    $\begingroup$ the US military does have the capacity today to fuel planes in flight, it's conceivable that other functions that need an airport can also be done in flight such as cargo/passenger exchange. $\endgroup$
    – Seserous
    Jun 10, 2018 at 22:11
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    $\begingroup$ billionaires, ... announce the creation of an aircraft-based civilization and maybe the country can apply for international aid isn't going to go down well. Who exactly would give aid to an elitist club of people who want to form their own country ? $\endgroup$ Jun 10, 2018 at 23:28
  • $\begingroup$ Engineer your aircraft to fly as high as possible, and hope that Earth's nations don't mind. You mean like a U2 or SR-71 ? What country could possibly mind a different country (the billionaires club or whatever) flying over them at altitude ? Everyone. Expect to be fired at by ever increasingly high tech missiles. $\endgroup$ Jun 10, 2018 at 23:31
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    $\begingroup$ Aircraft-based? No. Spacecraft-based? Yes. After all, we actually are living on a very large spacecraft named the Earth: all we need to figure out is how small can we make a spacecraft able to sustain a civilization. $\endgroup$
    – AlexP
    Jun 10, 2018 at 23:46

4 Answers 4


Physical Concerns

If you have already read about lighter than air vehicles (LTAV) in the 1930s, you know that they are very vulnerable to weather. This is why, to my understanding, they were abandoned.

However, predictive weather radar has improved significantly in resolution and accuracy. I can imagine the floating civilization always moving to stay in the clearest part of the weather track.

Interactive Future Radar

Another concern is air envelope weight. I'm going to imagine you using handwavium for your envelope : maybe some next-generation waterproof weaveable aerogel. Even neglecting infrastructure, depending on the height of your floating civilization, you will need a very large displaced air volume.

  • 1,000 feet: 1,700 cubic feet per hundred pounds
  • 5,000 feet: 2,000 cubic feet per hundred pounds
  • 10,000 feet: 2,500 cubic feet per hundred pounds

Political Concerns

The altitudes at which an LTAV city would work physically are in the middle of the aviation range of altitudes. Internationally, certain paths have published altitudes and there are levels of separation between traffic. It may be possible for your civilization to negotiate to have a Notice to Airmen (NOTAM) issued directing flights away from the city.

Flight Levels

I imagine most nations would want to refuse a request for a city to float over their land. However, if the city is organized by an institution that does business and has leverage almost everywhere (think of an Exxon or other multi-national energy company), then I can imagine them being able to negotiate fly-over requests with most countries.

Economic Concerns

If the city was an international station, like the International Space Station or international antarctic stations, then it seems plausible that universities and governments would provide most of the operating income for the station.

As a suggestion to what kind of research a floating city might accomplish: they could focus on climate research or climate change research, or maybe are evaluating the effectiveness of political/technological improvements that are supposed to reverse climate change.

The city doesn't have to be the best solution to the problem. We live in a political world where the best solution is often not the one we go with.

Operating Costs

Replacement helium will likely be your most frequent material cost. At $450 USD per 1,300 cubic feet according to Quora your cost would be:

  • 1,000 ft: $575 per hundred pounds of weight being carried by the city

  • 5,000 ft: $680 per hundred pounds

  • 10,000 ft: $865 per hundred pounds (all values rounded)

According to this YouTube answer, and assuming your LTAV helium envelope was made of something similar to Mylar in impermeability, the civilization would need to replace the whole volume of helium approximately every second week. That would make annual helium cost $15,000/$18,000/$23,000 USD for the three altitudes mentioned before. Multiplied by the weight of the rest of the settlement in hundreds of pounds.

Assuming the flying city had the $125 million per year maintenance budget of the International Space Station, how big could the aircraft based civilization be? Between 418 tons at low altitudes to 280 tons at the higher altitude.

How Much Will Infrastructure Weigh

Again, excluding the helium envelope, it would be nice to know what is required to sustain residents at this high altitude civilization. It will be cold and air will be thin. A good example of structures built for this purpose would be the McMurdo Station modules in the Antarctic. These had to be able to do the job, but also be small enough to fit into the 30,000 pound footprint of a C-130 delivery vehicle.

Given an International Space Station maintenance budget of $125 million per year to spend on helium, you could have between 18 and 27 McMurdo Station style modules for your floating civilization.

You would probably want to cut out an allowance for aircraft to arrive and depart the floating city. Even at 10,000 feet altitude, the aircraft based civilization is within reach of propeller aircraft. A few aircraft weights for reference: a six-passenger Learjet 24 is about 6.5 tons. An Airbus A300 (323 passengers) weighs about 70 tons.

Also, you would want weight for people and supplies.


From a hard-science perspective, you might really want to think through it. Especially the material holding all the helium keeping the city afloat. It would be very easy to drive up weight and cost there.

It is realistic that someone motivated with a will to make it happen and good international connections could make such a place possible. Yes.

  • $\begingroup$ Does this account for food, water, and waste services? Or is that cost lost in the "noise" of importing so much helium? Also, does the world have sufficient helium reserves to accommodate this city? $\endgroup$
    – CaM
    Jun 11, 2018 at 20:42
  • $\begingroup$ Are you pricing pure medical grade helium or balloon gas? $\endgroup$
    – Andrey
    Jun 11, 2018 at 21:21
  • $\begingroup$ How about we use a flying fusion reactor? We separate moisture int he air. Feed the o2 as air into the ships, we need extra air at altitude. Fuse the hydrogen into helium Use the helium to stay afloat,and use the power for maneuvering jets, and other stuff $\endgroup$
    – Andrey
    Jun 11, 2018 at 21:25
  • $\begingroup$ @Andrey I just got it from the quora post. I'd have to check. $\endgroup$ Jun 13, 2018 at 0:24
  • $\begingroup$ @CaM using the ISS and McMurdo budgets as models, supplies and salaries seem to run at the same level as maintenance. But there is some variance, so I thought I'd exclude that. $\endgroup$ Jun 13, 2018 at 0:26

They cannot attain self-sufficiency

...and thus will fail.

Civilization is heavy. Very very heavy. Earth's atmosphere doesn't like to support heavy things without lots of energy expended. As an example of how heavy, a single 1000-ton press used to make kinds of useful stuff, weighs 230 tons. This is just the equipment itself. This is very close to a Boeing 747 at 202 tons. While the payload of a freighter 747 is enough to lift the mass of the press, it can't support the huge loads exerted when the press is in operation, nor carry any of the materials that the press will operate on.

The inability to create new planes/airships without ground industry means that this newly declared nation will fail as soon as some other nation(s) decide to deny them access to their airspace and ports. Without fuel, they will be grounded in days.

Political Considerations

In order for a country to be recognized as a country, other countries have to acknowledge it as such. This acknowledgement is based on many complex factors but basically amounts to "Can I conquer you and would it be expensive to do so?" and "are you a peer?" if the answer is "Yes and it's easy" and "No, you're not", then no one will acknowledge you. Most any modern airforce could knock this new country out of the sky. Further, statehood is dependent on controlling land which your new country by definition cannot do. Thus, you lack standing to gain entry into the gentlemen's club that is international politics.

Also, acknowledging an entirely airborne country sets some unwelcome precedents. If any rich guy can build a big plane then declare themselves sovereign, then they'll all do it. This adds complication to an already complicated international environment. These nations also know that losing the ability to control the world's richest people will only lead to problems.

Durability of Airframes

Each aircraft has a service life of so hours of flight time. For commercial aircraft, this is measured in flight hours or cycles (take-off, fly, land). Aircraft that are constantly in the air will chew through those cycles very quickly.

There's too many ways for this to fail. Nature's best flyers still land to lay eggs and take a breather.


An aircraft based nation wouldn't work, because the lively hood of your nation would be directly tied to the amount of fuel imports you could get from all other nations. You provide no direct benefits, only benefiting the wealthy who live up there and act as basically a huge money sink. Its also going to be freezing up that high and everyone who wants to go outside would probably need to wear a insulating suit and a gas mask so they can breath. Basically you have a giant floating hotel where rich people can socialize, but why would they need to do that when they can just fly around in private jets with the rich people whose company they already enjoy?

I recommend going up even higher, into space and constructing a space elevator. At the top of your elevator is basically a huge space platform which forms a new nation that acts as the gateway to space for all ground based nations. This would bring you a ton of income as it drastically reduces the cost to launch a space craft (You could elevator the spacecraft up, or construct it up there). The construction of your new nation would also be easier since you can use your own space elevator to lift everything up, and the view would still be amazing. I believe the idea is considered to be feasible due to the strength of carbon nano tubes, but no one is able to construct a carbon nano tube strand longer than a meter yet. https://en.wikipedia.org/wiki/Space_elevator

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    $\begingroup$ Probably better to build a floating city on the ocean. A floating air civ where the ground is habitable is a money sink. $\endgroup$
    – Daniel
    Jun 12, 2018 at 3:14

I think there needs to be a true need for such a thing. The cost of such creations is going to be prohibitive. Wanting to do it just cause it'd be so cool doesn't seem like enough.

It might work if these billionaires were only making flying mansions for themselves, but they likely wouldn't require the kind of changes to the law you're talking about. There may be a number of these shy-homes, and they may want to buy a large area they could own, and freely fly over, but not a whole nation. Perhaps an airborne culture, as in a lot of people do it, there's a Sky Mansion Fancy magazine, but not done for the vast majority.

For a full civilization - thousands, millions of people - to move to the sky, I think there would have to be a damn good reason.

  • $\begingroup$ I agree, the only real reason I can see humanity migrating to the skies is if some kind of cataclysmic event made it impossible for any human to survive on the ground... or removed the ground entirely $\endgroup$ Jun 11, 2018 at 23:10

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