no it didnt actually fly out, i managed to grab it with my other hand and squeeze it shut, just in time! but i didnt like how it was pointed right at me and really close to my face!
it didnt fill up with air, the other times i have flown i didnt even have to empty, i just made the mistake of eating the wrong food before hand, and not taking my immodium at the right time. The cabin pressure doesnt really change that much, its just like when you go up the mountain and your ears pop, it stays pretty equal.
I guess my stomach felt the same, i get kind of motion sick so i had that going on, but that has nothing to do with having had surgery, ive always been like that.
I do think its weird, that once i get off the plane, i still feel like im moving for a while, its really odd.