I use trains to move around within my country, from a couple of hours to 4 or 5 for some long weekend trips.

I've been trying my best to stick to trains for longer trips but it's not easy: it takes a lot longer (and that's, well, expected and the least of the issues), it's less confortable (I took some night trains and the quality of my rest was very bad, so much so it impacts the quality of my first day abroad) but most of all, it's not less, not as mu ch as, but MORE expensive than planes.

I keep myself motivated by running this https://lowtrip.fr/ and keeping a lifelong count of the CO2 I've contributed to.

It's essentially a luxury though.