Paisley: welcome to PPRUNE, but your first post seems a little confused.
What on earth makes you think that "Irish aviation law" is the reason why Aer Arann is not flying to Angers?
You should be aware that (with the exception of PSO routes to certain Mediterranean islands
) any European airline can operate service to or between any other European countries.
Surely this was simply a commercial decision by the airline (perhaps based on lower-than-expected forward bookings, I don't know) that they could use their fleet better on other routes (e.g. Nantes, Cardiff,...)?
See, for example, a couple of the comments on
this thread.
I see no ulterior motive here. Perhaps they could have done their marketing homework a bit more thoroughly, but airlines launch and then stop routes all the time. No need to devise a "coq-a-l'ane" story to explain it in this case.
C.