How do the new planes get here?

I would guess the reenland route

............usually (if weather conditions permit) non-stop from Seattle to Dublin roughly routing over southern British Columbia, central Alberta, central Saskatchewan, northern Manitoba, close to Iqaluit in Nunavut, all in Canada, then over the southern part of Greenland, close to Iceland towards Dublin. JK

Thanks for your help Globemaster, much appreciated.

I wasn't sure if the 737-800's had the fuel capacity of doing a non-stop journey from Seattle.

I have noticed that most new planes seem to leave Seattle late in the evening and arrive in Dublin late afternoon the following day.

If you're interested in things like this I'd recommend reading No Frills, The Truth Behind the Low-Cost Revolution in the Skies
http://www.amazon.co.uk/No-Frills-Behind-Low-Cost-Revolution/dp/0753510448.

Great book that answers EVERY question about the low fares business.

Thank you Rich00cap for this information.