I did change. I dropped from 35-40 flights in 12 months (really not good, in more ways than one) to 3-4. Still too many. But getting there.
You don't have to be a vegan hermit to have an impact. Eating a little less meat, foregoing one flight, and biking to work once a week is better than not doing anything and that's great.
I am vegan. Probably 10-20% of my meals end up being vegetarian (usually with a minor ingredient like trace milk in a sauce).
This is simply out of practicality - we're talking stuff like, going to a restaurant with friends and there are no vegan options.
If everyone did that 80%, the ecosystem would (as it _already has!_) change so much that 100% would be trivial.
I used to think that it's pointless to do anything because no-one will follow you.
That has been empirically proven to be complete bollocks over the past few years. Go all in. I will follow, they will follow. It's time.
However, my wife is Chinese so of course she wants to see her family once a year. That means at least four flights. However we usually take the opportunity to travel whilst we're in China which adds another two flights each.
To balance this, we usually try to holiday in the UK when we can, which of course means we don't need to fly.