Go to a military surplus shop, buy a tank tool bag for a tenner and fill it with clothes.
Anything else carry it on the plane in a rucksack.
Though a tank tool bag probably wouldn't be an issue unless it was in patterned camo if you travel a lot there are some parts of the world where military or military style clothing and equipment is prohibited (including quite a few tropical islands and similar).


(dive gear on way home is always never quite dry)