In the UK the Conservative and Labour political parties are trying to seize the intiative on green policies. The Conservatives have proposed adding VAT to domestic flights, a special tax on airline fuel and green airmiles accounts.  The Labour party is hinting at carrots rather than sticks.

I think it will have to be a mixture of incentives and penalties in order to change travellers behaviour.   What carrots will make you want to be a greener traveller and which sticks will force you to be a greener traveller?