You should wear all your knickers to travel in. You may need very loose and wide trousers on top, but at least it will save the luggage allowance in packing them.

Also what everyone else seems to do is go through security and then buy another suitcase worth's of stuff in the duty free shops, which they then insist has to go in the overhead lockers, although so far, I have noted that there is a distinct lack of knitting patterns in said shops.