Well, their other routes are places like NYC, Boston, Chicago i.e. Irish-American strongholds with a lot of recent Irish migrants as well with San Francisco thrown in as a nod to the Silicon Valley corporate presence in Ireland.

Washington doesn't fit in there. I don't even get the sense the UA flight is *huge* or else it would be a 777 rather than a 757. So you add 4 weekly flights in the summer i.e. when government travel is at its lowest ebb. Dunno, who is it aimed at?