Nicer and cleaner version of a standard Japanese capsule hotel with an airliner motif. Stayed in first class cabin for little less than 4000 yen, and it was comfortable and just the right amount of space if all you need is a place to sleep and some space to stand up and change your clothes. Other cabins like business class looked a bit tight. I assume premium economy is completely a capsule type, so I wouldn’t really recommend that if you need wiggle room.
Bathrooms, big bath, showers were nice.