Ryanair Shannon pax
I don't have access to Ryanair figures just considerable anecdotal evidence. Ryanair carried 1.9m pax at Shannon at the peak of it's operation there. Clearly they don't all live in Shannon, Ennis and Sixmilebridge. In general Cork leaked passengers to Beauvais, Prestwick, Malaga, Faro and Murcia as they were the routes where the price differential was greatest.
Reasons for these travel patterns varied but it was usually along the lines of "I'd prefer to fly from Cork but my friend booked me out of Shannon" or " all the seats from Cork were gone" meaning all the cheap seats were gone.
The Polish routes were also popular with those anxious to save a few euro. Now that the fares war is over many of these peope are staying at home.