I was on a flight last week from LAS to PHL, and the guy next to me in FC brought along with him what seemed to be a memory foam type pad for the seat. It packed up real nice, and I thought it was a great idea. Anyone ever bring something like this along and if so, any recommendations on what kind to get? I am a heavier guy, and on 4 hr plus flights, I do start to get uncomfortable....

Thanks.