EASA
The European Union Aviation Safety Agency writes the common safety rules for the EU member states plus Norway, Iceland, Switzerland and Liechtenstein, covering aircraft certification, maintenance, pilot licensing and commercial operations. National authorities such as Germany's LBA or France's DGAC issue AOCs under EASA rules. For a charter customer, an EASA AOC signals a regime broadly comparable to FAA Part 135, with its own crew duty limits and a mandatory safety management system. Since Brexit the UK CAA runs a separate but very similar rulebook, so a UK operator flying into Europe and an EU operator flying into Britain each need permissions from the other side.