I frequently wear whatever I want to wear on the ground. A pair of slacks which can be washed and worn at my destination (assuming they are loose and not held up by a tight belt) takes precedence over a sweatsuit which has no use once I arrive.
I like to wear a seersucker suit when I travel. If I sleep, the jacket comes off. I will probably wear a sweater vest or cardigan and one of my softer cotton shirts. Regardless, I find seersucker to be more comfortable than conventional cotton or poly/wool trousers.