I had a trip from NY to FL flying, and just the stress and anxiety of all the details of getting on the flight and making sure I eat enough was my concern. When I did the TSA check, I did the scanner, and JFK/FL both asked about it, and I flashed them the reason why. I didn't really care about showing anyone because, personally for me, it just doesn't seem like a big deal. I keep my shirt down usually, but for emptying and questions about it, I lift up the shirt and deal with business.
Personally for me, I was in the hospital for months, so a lot of people have seen it, and I've grown accustomed to just keeping a tank top on halfway to keep an eye on the liquid output. Visually seeing it for me is more comfortable than having a shirt over it. But out in public, I do keep the shirt down.
My trip to FL was the first flight in years because I usually just drive everywhere, but after two years of being in the hospital, rehabs, and home not doing much, this was the first flight and away from home feeling, so there were a lot of other things I was worried about besides the bag. I made sure to eat enough, be comfortable in an airline seat instead of a recliner for 2 hours, and the travels to and from the airports. Just to have enough energy to get there was my main concern. Showing off the bag if there were questions was just something to add. My ileostomy surgery was in September 2022, and my first trip after was December 2024. I wasn't allowed to drive or be in public because of infection until October 2024.
You do what feels right, but I would rather not be in a private screening room and just get it over with. I make sure to install a new bag the day before so it'll stay on a little longer than an older bag that is definitely due for a change. Why add the concern of leaking when you prep the day before?