B19, there are many differences in aviation between European countries. They all grapple with overregulation and mostly the infrastructure is private or fee-based. Beyond that there is limited uniformity.
English is used at international airports but often the local language is mandatory at local airports - so people don't have to learn a foreign language to be a pilot. ATC and similar is substantially different between countries. Some have pilot-controlled airports like in the US, and airports that people can use 24 hrs a day. More often there are opening hours, some form of ATC requirement, and flights must be recorded for the purpose of government audit. In Germany for instance no flying is permitted unless from a permitted airport with a 'flugleiter' (flight leader) or ATC observing the operation. VFR chart quality and uniformity is generally poor. Flight plans are generally (but not always) required between countries despite no border controls for travelers moving between the same countries on the ground. As a result there is a tendency for any long distance flight to be done with continuous ATC contact (something like US Flight Following) even when VFR.
So long distance GA flying within the EU is possible but procedurally complex. Some people find IFR to be the solution, because its puts the plane in the system and ATC has to find a routing. The downside is that requirements for both pilot and plane in European IFR are 'over the top' which drives the costs way up. The upside is that relatively short distances put the plane in completely different culture, so there are rewards for those patient enough to deal with the bureaucracy and able to spend the money.
Hope that is of some use or interest.