I just did a backpack trip with a cotton skirt I sewed myself from a sheet. It worked great. It was basically a quarter circle skirt, about the easiest thing to make since you don't need a pattern. I'm out west so cotton worked fine. The skirt was below the knee so when I sat down I could grab the back and wedge it between my legs to hide my underwear. It was long enough to keep my legs from getting sunburned but still airy. I sewed two grossgrain ribbons on the inside that I could use to shorten the skirt in front, kind of like the tabs in your shirt sleeves. My skirt could be whatever length I wanted, at least in the front. It got really hot and humid though and I didn't like my thighs rubbing together. So I wore running shorts underneath and used the skirt to prevent sunburn. I found a silk skirt at the thrift store. I think in the future I will bring that. It's a lot lighter and airier.

I was hiking on the PCT on this trip. I saw a thru-hiker wearing a gold sequin skirt. I think really any skirt can work.