In relation to discussion about Ryanair's stance to other low cost airline coming into the Republic of Ireland:
They will retailiate if they can serve the destination (slots) and usually only if they see route as being commercially attractive. It seems if it's a significant LCC competitor like easyJet or Wizz they'll pull out all the stops to push them out.
Yes they don't react to Eurowings, Norwegian, Transavia as mentioned. There are specific reasons here. Eurowings fly to Dusseldorf, and Ryanair do not have slots there, besides Lufthansa group defend their patch very well, we've seen that in Frankfurt and Munich. Ryanair see lower hanging fruit elsewhere. Transavia, same story Ryanair can't get slots at Orly, otherwise they'd be all over this for sure. Norwegian is an interesting one. The brand is strong in Scandinavia and those routes can be thin for non Scandinavian airlines. Ryanair isn't huge in say Oslo, so going to war with Norwegian may not be a good game plan.
In the cases of Wizz, Go, easyJet and bmibaby. They have responded rigourously to each of these. Bmibaby at Cork was an exception, but at that time Ryanair had no base at Cork and clearly didn't have the sort of deal that they have now. They chased bmibaby off DUB/EMA which was at a time a key WW route ..
And to Knock. Ryanair clearly have a special relationship with the airport, which simply is amazing. After Dublin, Knock is the closest airport to where MOL comes from. That might be Pudsey of it, but he seems to want to see the airport progress. The airport introduced the ADF back in the 1990s and Ryanair threatened to withdraw their London route (that's an they had then). The airport said that's fine and had other airlines lined up if Ryanair exited. It never came to pass and Ryanair is solidly supporting the airport. In the case of Norwich, you can be sure if Ryanair accept an ADF , they'll have done so on the basis of attractive commercials. Like somebody said their are exceptions to ever rule...