I fly a lot of 737's IAD-DFW, but recently took a MD80. Usually when I descend in a 737, the ear pressure pain is pretty intense, and they can feel stuffed up for hours after. But in the MD80, it was significantly more comfortable. I do the same routine in both - gum, swallowing water, etc... the only difference was the plane. When I landed, my ears felt like nothing had happened at all.

Just curious if any engineers out there know why? I've noticed I tend to have more ear pain in Boeing planes in general compared to regional jets, etc.