It would be better to incentivise air carriers to focus on having cleaner planes and penalise those that don’t.
There is no such thing as a clean aeroplane (beyond hyper specialised solar panel powered single seaters).
And @ObiWomKenobi I think flying to Greece is far enough, compared to Italy which is really only ~24h on a train, that it becomes a much more sympathetic issue. Still problematic but far less easy to blame on the individual. Edit: and yeah, the humour didn't come over, so sorry for missing that