Passengers over 12 years who fly from Ireland West Airport Knock are charged €10 Airport Fee. I'm don't think that FR include this when you book flights. I think you have to pay it at Check-In. I would say it's going to be like that here as well.
Sorry my mistake this is true. Come to think of it Newquay airport imposes the extra charge too where FR operate to Alicante. It is just recently, there's been rumours of FR threatening to pull out of DSA if they introduced an additional charge for departing passengers. . . Whether true or not no-one knows, but should they return to MME then they will certainly continue to sell the DSA flights should a charge be introduced.