Your passport is perfectly valid ID for flying. You can also get a US passport card. I used to carry one when I was in Japan. Anytime I had to show ID, the per

Your passport is perfectly valid ID for flying. You can also get a US passport card. I used to carry one when I was in Japan. Anytime I had to show ID, the person would say "oh, diplomat!" because its looks more like a US federal ID card than a passport. But it should also work in place of a "Real ID", and is easier to carry than a full passport.