I meant europe that is still reachable by plane

Huh? What's stopping anyone to reach Romania by plane? Or Bulgaria? Or Hungary? Or Slovakia?

Or was it a joke I'm not American enough to understand?

Thought you meant russia/belarus. Didn’t know they put them in bolgaria and co tho considering how low they go in price it makes sense

Eastern Europe is not just ex-USSR countries, and even there you can still travel by plane. Only Russia, Ukraine and Belarus have closed airspace.