I don't think that's true. Essentially the problem is that the US government requires airlines to hand over information that it is illegal for the airlines to hand over under EU privacy laws -- so the solution is that the information is handed over after the passengers have left EU-member airspace. That, I believe, is the same regardless of whether the airline is American or European.

So the flight has to be partway over the Atlantic before the no-fly list can be checked, hence the extra stop in Bangor if a hit is found -- they can't just pull the passenger off the flight before it leaves.