It is official Sioux City SUX.  The airport code for Sioux Gateway Airport is SUX.  Anytime you want to search for a flight you get to enter that fun three letter airport code.  The closest airport to me is Orlando International and their airport code is MCO.  SUX is much more fun.  Sioux City was given some choices of alternate codes.  GAY was one of them.  Would you rather fly into an airport that SUX or one that is GAY?   Sioux City said they will stick with SUX.