There's a degree of near-xenophobia developing through this thread. I am sure that Aer Lingus has more than a few UK resident and UK-taxpaying pilots on its seniority list, just as British Airways and Virgin Atlantic have pilots resident in France, Netherlands and far beyond on theirs. If those existing Aer Lingus pilots start to fly to and from Manchester instead of commuting back and forth to Dublin before every shift or block of shifts, who exactly has lost out here?
And there is already a major European airline resident in that figurative broom-cupboard above the coffee shop at Shoreham (not literally). SAS Ireland operating out of Heathrow. It's perhaps at this point that I should put on my tin hat and run for cover.