I have no function from the waist, so I have a catheter and ileostomy. I fly regularly and show check-in service desk and explain my need to change my bag, etc., in flight. I find preparation is the go. They always, whenever possible, upgrade me! They don't people around you complaining, and I take my precut wafers (don't put scissors in your hand luggage). I have "blueies" which you probably know have a plastic back (blue hence the name) and have white padding placed on my lap. I place it close under the flange of my stoma. I try to have everything prepared, including putting na scent drops in my bag before I change and put Huggies wipes around the perimeter of my flange to catch any ooze, and have my waste disposal bag ready plus about 6 wipes. I can, in less than 60 seconds, whip off the used bag, wipe the offending area, and spray with Cavillon Plus. I put my new bag on in one foul swoop! Then I quickly stuff everything in the waste bag, pull down my top, and fold up my blueie, which doesn't get dirty because of the Huggies. It's just a case of quickly putting everything away and sanitizing my hands. The air stewards will discreetly dispose of your waste, just remind them to put on gloves!
Done! I also use the side of the blueie to fold over the area like a privacy screen so no one can see, and the na scent works for odor 3-6 drops depending on your bag size. I use Hollister closed opaque midi bags. Just remember to only take a travel-size na scent or Cavillon if you use them on the plane and fill from your main bag in your checked luggage as you need it. Etiquette obviously dictates keep it discrete, for your dignity as well as others, and don't do it during meals! LOL.
Catheters are a different subject, but if you have one and need help, contact me.