Interesting discussion. I can't really offer more on the type of masking that hasn't already been spoken to here, but for (at least) the transit portion, might I offer this...
01) On a plane, consider making regular trips to the washroom (yeah, kind of a pain) and taking your mask off in there for a few moments...
02) Air movement is your friend. I often carry a USB fan and use it to blow air at me. I find it easier to breath (mask or no) when there is a cool breeze aimed at my face)
03) Keep hydrated... while we need to keep our masks on, a few quick sips of something cool often helps me when I am out and about.
04) Along with the above, I try to keep some hard candy in my mouth to keep it from drying. It just seems to help me.
I haven't been on a plane during covid, but I'm assuming these types of daily activity help me go through long periods of mask wearing.