@RAT-5, that wasn't their own tax, it was a charge levied on airlines by the European Commission which Ryanair decided to pass on to the customer. The cost of such catastrophes is neither the responsibility of the airlines or passengers so I don't think either should have to pay it, but either way Ryanair isn't charging it by choice and doesn't benefit financially from it as it would from say charging for check-in.
As for the tax itself, I think it's right to abolish it. Airlines should make some contribution for tackling their carbon footprint and already do so through the Emissions Trading Scheme, but taxing passengers only serves to act as a disincentive to travel by air which may be fine for countries on the continent and even the UK but there are only 2 ways of getting to/from Ireland and the main one is by air. So we're taxing tourists and business travellers for coming here, which sends out the wrong message and inevitably leads to them going elsewhere so whatever revenue is brought in from the tax is outweighed by the money taken out of the economy.