It’s a tough call. Other EU countries ignore EU law while we follow the rules. Surely we will be unleashed next year to follow our own path but then no doubt the EU will still think they have full control over a sovereign nation that is outside the EU if we want a trade deal.
The EU position is that for Flybe to get a domestic concession then all airlines get a concession so giving tax breaks to profitable airlines like Easyjet and BA.
UK airports follow different rules as Inverness for example is exempted while Aberdeen gets the tax added to their domestic flights.