Oh, can I relate - even before UC - with just anxiety causing diarrhea.
You wrote - "Then I started thinking what if my colon acts up during landing or take off & I can't get to a bathroom."Don't let anyone tell you you can't go to the bathroom when taking off or landing. You just INSIST. (I told one attendant she could clean up after me instead or let me go LOL)
Shannon has the right idea - what works for me also. Eat only about 4 hours before your flight - you know what you can or can't eat that will affect you most. I take Imodium every 4 hours until I know I am safely in hotel or ? with a bathroom. I have flown about 6 times that way and never had a problem.
My doc gave me Xanax for anxiety also - small doses help. Deep breathing especially if you are in a car waiting to get to a bathroom really helps me!!
It is not easy to relax but that is the best you can do. AND eating less.
ElaineNY