I generally haven’t had much bother travelling on a plane with my ileostomy. I have travelled to Vegas, New York and Mexico with no problems. I would say however that aeroplane toilets are not designed for us. They are tiny, and the flush is terrible. However I have always managed by emptying fully before boarding the plane then just a few times as required on board, depending on what I have eaten.
As for airport security, again I haven’t had any bother until recently. I have a card from my GP stating my surgery type etc and the position of my medical appliance on my body. However during a trip to NYC with my partner I forgot to bring it. Travelling to NYC was ok but coming back was a different story. Walking through the body scanner I was asked to step aside to be examined by the lady security officer (obviously because they noticed my pouch). I explained that I have an ileostomy, which she appeared not to understand what that was. She asked me to point to where on my body it is, which I did. She then asked me could I touch my appliance “without exposing myself”. I did so as best I could. She then swabbed my hands for drugs. Moral of story is to get the card from your GP which explains things in different languages. It may just save you some embarrassment.