I stopped flying about a year ago and have been very happy with that decision. I like travelling by train, which takes longer but is much more comfortable.
The main reason I stopped is because we as scientists have been trying to convince people that there are serious problems with our current way of living, and now that people are finally listening we’re not even setting the right example. If we don’t even take our own claims seriously enough to change our behavior, how can we hope that other people will?
I did a PhD in mathematics, working on the moduli space of curves. Now I work in mathematics education as a teacher and researcher.