Never had any issues with my ileostomy when flying. I've been on several 10+ hour flights.
One of these trips was to Southeast Asia, where it was very warm and humid. Didn't have any problems with the bag coming off, not even when swimming in the pool. But then again, the bag coming off by itself has never been an issue for me.
The one thing I would recommend when flying is to pack all your bags and things you might need (wafers, etc) in your carry on luggage, so that if your suitcase would happen to get lost, you still have everything you need. Just as a precautionary measure.
Post Edited (07kr5) : 2/23/2018 10:23:05 AM (GMT-7)