I understand the anxiety of flying. You need the comfort of knowing you are prepared. This is what I do...
In my purse, I pack a spare kit containing a pouch, flange, wet wipe, and underwear packed inside a ziplock baggie for garbage disposal. I pack a tiny bottle of deodorant drops (M9) and a tiny deodorizer spray (pooh pooh). I wear dark, loose clothes and a long top to cover up if I have a leak and stains. I put a new appliance on with a new unclogged filter system (Coloplast Mio Pouch) that morning to avoid gas buildup inside the bag. I eat low fiber that day (no salad, vegetables, or garlic) so I have less output. Yogurt is good to eat because it reduces odors. Pack your own food if allowed. I go to the washroom just before I board the plane and use extra deodorizer drops. Buy a large water bottle before boarding and sip throughout the flight to stay hydrated! Pack enough supplies in your carry-on for your trip, plus an additional two weeks' supply in case of emergency and you can't go back home as planned. Being prepared lowers anxiety. I fly all the time for 30 years and have had only one small leak that I caught before boarding. You will be fine!