While they were uncomfortable, they definitely helped reduce swelling in my ankles though I felt so old wearing them. (travelfashiongirl.com)
From what I'm told, compression tights should also help reduce swelling of the legs during air travel, however, for whatever reason this wasn't what I experienced. (cyclingtips.com)
Finally, elevating your foot above the level of your heart will also help reduce swelling. (sportstarsmag.com)