840 - its probably for the best if air travel to the west is consolidated into two airports. Sligo is already gone with the impending loss of the PSO and while RE have yet to say it publicly, they must know that time is up for Galway too. I'd guess most of GWY's passenger traffic would go to Shannon, with some to Knock and Dublin also. 180,000 pax or so divided up won't make a huge difference to any of these airports but having fewer gives the remaining airports a better opportunity to establish themselves long term.