The EU is planning to include aviation in an emissions trading scheme from 2011/12, which will add about €10 (short haul) to €40 (long haul) to the cost of flights; this will be on top of whatever fuel surcharges are imposed. It seems to me that there will be an additional charge no matter what the airlines do; it will be a blunt instrument, with no recognition of the peripherality of certain countries or regions (Ireland, Cyprus, Malta, for example) or their dependence on aviation. How consistent will this be with the EU principle of free movement of goods/persons?
Here's FR's view on it, although you need hardly open the link to guess what this is!
Basically, he says it will fail unless the rest of the world is involved. And of course, there are two chances of the Americans rowing in with this; basically, the American stance is "sod off" and you can expect this to figure quite significantly in upcoming talks between the EU and US on the next phase of Open Skies; indeed, I wouldn't be surprise if the talks were scrapped on this very issue alone.
The plan is being put together by a German MEP (Green?), although I'm not clear what further hurdles (if any) it needs to get through before becoming law.