If you have to pack a kilt into a case for travelling, roll the kilt up into a roll like a sausage and put the kilt into the leg of a pair of tights or a stocking. The kilt can then be placed in the case at one of the long edges and so takes up less room and arrives crease free
If you find that it has got a bit creased, just hang it in the bathroom and run the shower hot for a few minutes. Any creases should drop out pretty easily.
Why is this any different to a woman packing a skirt to wear? They have laundry and ironing services for skirts etc on board anyway if it gets creased.
Kilt is a Scottish dress and wears mostly in Scotland and Ireland.
If you notice a slight crease, just hang it in the bathroom and let the shower run for a few minutes. Any crease should leave fairly easily.