I have heard of people rolling them inside a nylon hose (panty type not kilt type) before packing in their suit case. I just fold mine in half the long way with the pleats out (that's the way the pleats are used to bending)and lay it flat in my suit case between two other items to avoid any friction from the suitcase during travel. Seems to work great. Another thing I do if flying is to make sure any leakables in my shaving kit are in zip lock bags prior to leaving to avoid anything getting on the kilt, as cleaning one is not an easy task.

Enjoy your trip!