But I went flying in Slovenia once,
Murska Sobota by any chance? Beautiful airfield, I did circuits there in the local Super Cub. Delightful! You could see Hungary from the circuit.
Actually, in most of mainland Europe, it's much like flying from Texas to Florida. Presumably, you don't have Customs borders between the two, do you?
The Europeans have sensibly introduced frictionless borders between all the countries within what's called the Shengen Area. 26 countries, including Switzerland which isn't even in the EU, participate.
TOO