You can get a piece of special kilt luggage, such as this:
http://giftshop.scottishtartans.org/outfitter.htm

It allows you to store and transport the kilt rolled, rather than folded, to prevent creases.

Barring that, you can do much the same thing with the leg from a pair of women's pantyhose. Roll the kilt up pleats to the outside, into a tube and then put it inside the hose leg, to keep it all neat and in place.

Alternately, if you have room in your suitcase to lay the kilt flat neatly, without too much squishing, that should work of for short travels.

Whatever you do, just try to give yourself plenty of time to let the kilt hang once you reach your destination. That ought to work out any minor wrinkles that result from travel.