As the current way to set up an airline seems to involve contract crews on IOM registered, Bahamian-leased aircraft paid through a subsidiary in Lichtenstein, the whole thing is so obfuscated that no-one really knows who owns and runs what. Add in all the complicated agreements and conventions between nations and blocs and I don’t see much changing, really.
IAG, for one, seem to have seen this coming (or are fortuitous) as they are both in and out of the EU simultaneously...