|Aer Lingus aircraft, part of IAG group.|
Not many people know that Eire has for long had US immigration clearance on Irish soil, so US Immigration officers work in the Eire to clear Passengers, so the flight then becomes a domestic US flight from Eire onwards. This is partly a hangover from the days when Shannon one of the last land points in Western Europe would have many European propeller aircraft stopping there as a refuel point before the long slog over the Atlantic to Gander in Newfoundland.
So if you fly via Shannon, Dublin and now Cork you can clear US immigration and save hours in long queues. But recently Edinburgh has gained the same privileges and Norwegian using the new B737-800 Max have started to build a network of low cost flights to the US, they did have a loss leader launch of £49 oneway, but this was massively under cost and oversubscribed.
So if you want to fly from your regional airport, look at flights via Eire and save money, reduce stress and do things a little differently, a theme I keep harking back to