Is this a subject where aviation is not going to win? Aviation people say that aviation contributes only 3% of CO2 gases. Some people say that aviation will generate some 5% of all CO2 gases by 2050. How is that figure arrived at? By 2050 the airlines will be operating a plane that replaces the 787 - Compare the 787 planes that were new 43 years ago - 707s, Tridents, Il-62s.
Also planes' gases are worse because planes are up in the sky. Is it possible to disagree with scientists who make these claims? Is water vapour bad?
Aviation people should not have a go at agriculture either, because the people who are going after aviation will want to introduce compulsory meat-free days as well.