Originally Posted by
TheMadBrewer
Since they are coming in pre-cleared could it be easier for them to arrive at a "Domestic" terminal? (I know T2 also has Customs and Immigration but the bulk of flights are domestic) I don't know the setup at TBIT well enough to know if a flight without Customs/Immigration requirements is a big deal or not.
It's not a big deal. Instead of going down to immigration upon arriving at TBIT, you exit the gate area at the departure level and... that's it! You can walk out to curb side from departure level or go down to the domestic luggage claim - basically no different than any other terminal.
My guess why Aer Lingus stayed in T2... probably has something to do with its pending OneWorld membership. They are probably just waiting to be admitted so they can use the OW lounge in TBIT. No sense signing a contract to use another lounge when membership is already pending. Just wait a couple more month and then switch everything at once.