If you want people to give up flying you need to give them alternatives. I always choose train if it's available. And for meat we don't have to collectively give up meat, eating less meat (once or twice a week) would be totally efficient in limiting the CO2 emissions
It’s really not hard. I think the extreme emphasis on going veg/vegan is actually harmful. Just eat less, find good veg recipes, then eat a little less, etc. You can get 90% of the way there and not even miss it much if you do it gradually.