Question: Since this year, 2022, I am not a resident of Germany anymore. I am officially unregistered, and I haven't visited my home country since then. That doesn't mean that I gave up citizenship, however. I still have my German passport.

On Monday, I've a flight with transit through the US. United Airlines asks me for travel documents, and that involves entering a country of residence:

[![Screenshot of United web form](https://i.stack.imgur.com/z5Cf7.png)](https://i.stack.imgur.com/z5Cf7.png)

I don't have a country of residence. *What should I do? Can I even transit through the US?*

A United agent suggested that I contact the German embassy. It is weekend, though, and both the German as well as the American embassy are not available.

Update
======

In the end, I arrived at my destination without a problem, and I did use my layover in the US to leave the airport for a night. What country I specified as country of residence, I forgot, because I couldn't edit or see it anymore after I advanced in the form. I was asked for the country of residence when I got my tickets for the connecting flight. In that case, I specified France, no problem.

Answer: 
I'm adding this as an answer of what not to do, because you might not be aware of some fringe political/legal arguments people try to make in the US. There are people that refer to themselves as "Sovereign Citizens" and they talk about not being under the jurisdiction of any country's laws so they can do things such as "freely travel" or "non-commercially transit" the country without a need for driver's licenses, license plates on vehicles, etc. Basically they claim to be outside of the laws for any given city or state because they are their own country (or something like that).

This falls under the heading of "conspiracy theories" and if you want to research it, keep in mind that no legal entity in the US agrees with what they claim.

So, why bring it up? Well if you start telling officials that you don't have a country of residency/jurisdiction and you should be free to travel, etc, you're using some common phrases that might lump you in with this movement. It's the first thing I thought of when you said "you're not a resident of any country", but I'm probably biased from watching several videos about the sovereign citizen movement.

So, I agree with the other answers saying what you should do, but don't go around saying you're not a resident of any country without a little more explanation.
I think you are confusing 3 different things:

* citizenship (nation who issues your passport *and cannot* refuse you entry to their borders even if they leave the EU)
* residency (the place you keep your core possessions and sleep at night when not traveling)
* some set of beliefs you hold - not to diminish them in any way, but we need to clear up the fact that these 3 things are not the same.

Confusing these, or perhaps more aptly to "take a political stand" on something - will only result in refusal. Refusal means no more visa waiver, and paying $160 to apply for a visa when/if you want to visit the US in the future, and the wait, and the need to explain your planned activities in greater detail.

Residency is a statement of fact, and facts obviously cannot be about future things that may or may not happen. Therefore, "where you have been staying up to this point" is the answer they are looking for. And stating a residency places you under no obligation to live there in the future.

You just can't live *here*.

Immigration is keenly watchful for people who want to enter on a visitor visa or waiver, and then violate the terms of their visa by overstaying or seeking employment. If you even smell like a person like that, i.e. rootless, wandering, a continuous world traveler\*... they have every reason to refuse you. As such, a powerful part of any visitor application is a showing if facts that you have roots in another country and thus strong incentive to return there when your stated business is done.

\* unless you have an ocean-going boat and have arrived on it.