@hawkeye10,
There has to be some sort of logical seat size. The last flight I was on -- there was a very large man next to me -- way too large for his seat. As a result, he could not put down the arm rest because his body was so large it wouldn't allow it. Also his body then was overflowing into my seat.
Of course the plane was full and I was traveling with my daughter so I didn't want her by herself or want her next to this man. It was a red-eye and believe me in the morning my eyes were red.
It really isn't fair for a smaller person to have to give up part of their seat for someone larger -- I paid for a seat and should have full access to it. According to the airlines website they do not have any rules about oversized passenagers requiring to purchase another seat or purchase a seat in the rows with more room so those sitting next to them have to suffer.
I think I have an idea for the inventor on here -- something that prevents the person next to you from oozing into your space.
Not that even an average size person can fit comfortably in one of the seats. I have also heard certain airlines (to avoid the reclining situation) have taken out the reclining of the seats. I think soon there will be a standing room only flight.