If my suitcase is big enough, I lay the kilt in flat. If not I fold it top to bottom, or even fold it both side to side and top to bottom. If the rest of the belongings are packed in firmly so that nothing can move, a good woolen kilt comes out of the case some hours later, looking just as good as when it went in. Hang it up as usual and it won't even know it is away from home.

Martin