Comment by _DeadFred_

It's a challenging problem. Going back to when I was in aerospace even just with the FAA we had FAA west and FAA east, and they were treated as different entities within our company because they had such different approaches/understanding and then the EASA which was from our experience a protectionist entity that would look for gotchas on American competitors and not a neutral safety focused party and refused to recognized treaty obligated acceptance of FAA certification (and it was a big issue that the US refused to step in on our behalf and require the treaty be followed because the US authorities put safety first even though the US had agreed we were safe and had demonstrated it).