In my experience, when a flight is international then the checks end up being pretty similar to what you see with the TSA in an American airport. When they are regional then there's nothing happening.

(granted, that was dealing with a UK->US and US->UK flights)

I have the opposite experience:

First, regional and international flights always been in the same terminal and therefor the same check for me.

International...depends on a country:

Vietnam spent more time looking at my passport then looking at my luggage (actually didn't look at all, was talking to someone and not looking at the monitor).

Korea - leave everything in a bag, leave your shoes, easy-breezy.

Japan - the same as Korea.

Germany/Spain - was more worried that: I have place to say and plane ticket back and that I will be let into the US on my way back that what was in my bags.

Mexico - again, more time spent on documents than my bags, but I was subject to random search at the gate once...unpleasant.

In fact, even in the US TSA checks aren't the same: some airports let you leave everything in a bag, others will bitch about tiny wireless headphones left in a bag. Anyway, I'd say TSA will have the most ridiculous checks and number of people who have no idea how to go through TSA.

That's because the US required TSA like checks for flight in and out of the US.

From my experience in EU -> EU flights they pass your bags through the machine and a metal detector, and that's it

As far as I'm aware, America is the only country that makes you take your shoes off. Certainly it's not the norm.

Idk about now, but when I left Russia last time, not only I was asked to take my shoes off, but also walk on my toes.

Happens all around EU but its random like next 20 take shoes off but you see it often.

AFAIK, depending on the destination, the airline and other parameters, there will be air marshals. Contrary to the US, these are „normal“ special police, and they won’t do this on a regularly basis.

It's been about a decade, but when I spent some time flying around Europe I remember their airport security being considerably less onerous.

I recently went from North America -> Africa via Europe. I do have global entry, but i found the CDG experience to be more onerous than the one I have domestically in the US.

My memory is exactly like that, but also vague on this specific matter. Hence the question.

Water bottles paranoia we do, I suspect because it so profitable for the shops past security control.

But nothing like air marshals or TSA as they are described.