With the stick flags we run a light line
through the sleeve where the stick goes, then we put a few stitches through the flag and line
. Not sure that you always could buy a flag conveniently where you check in. I think we bought from United States Flag Store, good selection nut there are still some you cannot get easily like Cook Islands and Montserrat. We bought some extra red and blue British ensigns and cut and pasted (well actually sewed) to make some flags.