If I take the train, which is the most green transport (CO2 neutral) from one edge of europe to the other (e.g. Berlin to Sicily), the amount I pay is 500 euros and it takes me 35 hours.

If I fly the same distance it takes me 3 hours, and I pay 100 euros.

Heres the kicker, it costs me 100 euro to buy CO2 compensation and make the flight CO2 neutral, and whenever me and my spouse fly we always pay twice that so that we are actually carbon negative.

So everytime we fly we reduce the earths CO2 by one flight and still have 200 euros more in our bank account.