OT: I've always wondered why airplane seats are designed that make sleeping in them so uncomfortable, especially if they are not reclined. Is the seat shape due

OT: I've always wondered why airplane seats are designed that make sleeping in them so uncomfortable, especially if they are not reclined. Is the seat shape due to a safety requirement? The back of the seat curves forward, with the headrest being forward of the lower back. My neck gets sore just sitting upright sometimes, much less sleeping. Also, there is nothing keeping your head upright; some seats allow you to fold in the sides of the headrest, but the folded part is so far to the side that it really doesn't support my head. Compare airplane seats to automobile seats, which are much more comfortable for sleeping.