I ordered these socks for a trip to Europe. The last time I flew across the ocean, my ankles were frighteningly swollen for the entire week of my trip. This time, a tour company made our flight arrangements. They routed our return flight from Amsterdam to Houston (a 10 1/2 hour flight), then from Houston to Orlando. I wore the socks to travel both ways across the ocean and had no swelling problems.Medium socks fit my size 8 narrow feet. The socks are somewhat thick--like a heavy crew sock. I didn't want to wear them through the airport because they made my shoes too tight. I wore Sperry Top Siders on the plane that I don't normally wear with thick sox and kicked them off while in my seat. It was a little bit difficult putting the sox on. I wore a long skirt so that I didn't have to deal with pant legs. You would not be able to put them on under skinny jeans unless you put the socks on first. If buying for air travel, I would advise trying them on with the pants and shoes that you expect to wear on the plane.