I had an EDS friend who used to fly a lot and his tail bone basically slipped out of place. They were able to push it back in place (but he said, it wasn’t pretty!). On airplanes, I, too use a special cushion (it is U-shaped and I leave it open in the back. It can also be bent into different shapes to be used as a neck brace, pillow, etc. WAY cool gift from my hubby.