Please don`t start the whole "only one NI airport" debate again.
If I remember the debate stalled because one commercial enterprise is required to be forced to close so another commercial enterprise can then try and be successful. utter tosh and madness!
The bottom line is that Dublin airport is now very convenient to get to, whether by car or using public transport from Northern Ireland. We all live in a free market where we all have choices to travel from wherever is most convenient/cheapest for us, get used to it.
If Aldergrove think they could ever pose a real threat to Dublin they are in cuckoo land.