If you're flying economy, chances are your seat won't have a built-in foot rest, but bringing along your own could really change how you sleep on a flight (not to mention how you feel when you land). The adjustable straps on the Cstom Portable Foot Rest (£9) fasten over the tray table, and the slightly padded base acts as a sling for your legs. It works on most types of aircraft, and should be suitable for all but the tallest folk.