My experience of traveling with a suit is confined to trans-Atlantic trips using a 29" suitcase, so my advice for a short domestic flight may not be optimal, but, when I travel, I have the suit(s) with which I'm traveling dry cleaned, and I keep them in their plastic wrappings. To further isolate the suit from the rest of the contents of my suitcase, I use one of the garment bags in which my suit was packed by the store from which I bought it, packing the suit in its plastic wrapping on the dry cleaner's wire hanger (usually bulked out with cardboard for the shoulders and tissue paper for the arms) inside of the store bag. Ideally, the suit carrier from the store will be one that folds in thirds and zips shut (SuitSupply's garment bags are made this way), making it ideal for packing, thought I've done this with those that only fold in half.
Keep the plastic wrap, and use it to wrap the suit on the way home - it will minimize wrinkles, making it wearable after the trip is over (perhaps with a bit of steaming/ironing).