No problem. You can bring your own foot rest with the
Meyoung Airplane Foot Rest Hammock. I normally try everything I talk about on The Tech Guy, but I only learned about this gadget recently and had no airplane trip coming up. But the reviews for this are good on Amazon and one of the reviewers said they used it at home as a foot rest. That gave me an idea, why not hang it over a TV snack table I sometimes use when I watch TV. So I tried it, and it works fine to elevate my stocking feet. It will probably work fine too on long distance trains as long as you have a place to hang it from, like a snack table built into the back of the seat in front of you. On an airplane it can hang from the snack table arms to provide a hammock-like foot rest. And unlike some other travel gadgets, it doesn't make you look dorky, because probably no one will notice. It weighs only 3 oz and folds down to about 8" X 3" X 2" inch. The company says it will relax your feet and reduce pressure on your back. I can't prove the reduce pressure on your back, but it was very comfortable for my feet. I paid $13.99 for mine on Amazon here:
Giz Wiz Link. You pay exactly the same as anyone else, but The Giz Wiz gets a tiny credit to buy more stuff on Amazon to demo on shows. Thank you.