And that sucks. More freedom is good. More taxing won't help more people travel.

That is, of course, the intention here. But that's not a solution, its pretty regressive.

What kind of freedom are we talking about?

Every kg of CO2 you contribute to pushing out in the atmosphere is a little bit of freedom taken away from the generations coming after you that will have to deal with the consequences.

If airplane flights are inappropriately priced compared to the externalities they cause - which I’d argue is the case, as with any industry powered by fossil fuel - then taxes are a great way to deal with that.

What alternate solutions do you propose?

Negative externalities suck worse, especially when they are destroying our planet.

Assuming you have a $150 ticket, this would be 1% of the cost, and seems unlikely to change behavior.

Flying takes a pretty heavy toll on the environment, it should be discouraged as much as possible.

If people want to travel, the continent's already covered with roads and rail.

Is 3 euros, round trip, really going to incent different behavior?

The reactions in this thread really show why I'll never want to become a politicians. Half of the reactions here are "that's a regressive tax that'll kill our freedom", the other half being "that's not nearly expensive enough".

Which road do you take to Iceland or NYC from Paris?

Which definition of "discouraged as much as possible" means "prevented entirely"?

We may be at the point where we have to choose between the freedom to fly and the freedom to live on an inhabitable planet.

Generations from now, people will, if there are any left, look back on these bourgeois luxuries as a kind of grotesque oppulance, utterly out of whack with ecological reality.

That's something you just can't predict. No one knows what people will be thinking "generations from now". You seem to be projecting strongly.