EI have a partnership with JetBlue, so they would serve JFK, but has anyone read the small print about missed connections between two (semi) locost airlines?
I hope for BFS's sake that CO stays, but I don't think it will happen - once an airline starts to talk down a route, it isn't good for passenger confidence - and it doesnt look like a political solution will be (or can be) reached in time.
CO has to be Northern Ireland's main (or only) hope for transatlantic service - the airport play up the 'don't fly east to fly west' thing, but I think that as carlrsymington says, it is more about the links available at the other side of the pond.