I agree with comments that Aer Lingus should try long haul from Manchester via Ireland to the US on routes where there are no direct flights ex-Manchester. They could re-introduce all the US destinations they canned from Dublin..
Manchester-Dublin-San Francisco
Manchester-Dublin-LA
Manchester-Dublin-Washington DC
Manchester-Shannon-Boston (rather than originating in Dublin)
New routes..
Malaga-Dublin-Boston
Manchester-Dublin-Dallas
There are lot's of opportunities with the open skies agreement!!
All flights could go through US immigration in Ireland avoiding the long queues in the US
