Aer Lingus fly direct but there's never a lot of availability and our itinerary was Dublin-London-Chicago-San Fran *surface to Las Vegas-New York-London-Dublin. I am tired just typing that! P got the deals on the internal flights by booking the transatlantic with American Airlines...
U2 tickets are like gold dust over here! We are hoping we get to see them on our honeymoon somewhere. We went to Slane Castle on their last tour (a friend got tickets through work) and I honestly don't believe that concert could ever be topped, it was pure amazing! Padhraig saw them in Giants Stadium when he lived in NY too..
Get yourself in a sleeping mood and you will be fine, the eye mask and classical music did it for me..