I've flown to the Philippines a couple of times and travel to Leduc, Canada at least once a year to see my best friends. The best advice I can give you is this:
Make sure you keep a spare pouch and a spare change of clothes in your carry-on. If you use a cut-to-fit, like I do, make sure the flange is pre-cut (TSA won't allow the scissors in your carry-on stuff). I've had a few occasions where I've had to change my pouch out in an airport bathroom. So long as you're prepared, it's usually an easy in and out.
Some people will report air filling up their pouch during the flight due to change in altitude. I've never had this issue, but it's something to be aware of. A simple trip to the airplane bathroom to release the air is all it will take to fix that issue. I use a two-piece system, so it's a simple matter of cracking the pouch from the flange to let it out.
Personally, I try to eat very little when traveling, but that is 100% a "me" thing. I intermittent fast (because I'm a fatty), so it's more of a willpower kind of thing. I would recommend not eating heavy meals though just because during the flight and any layovers you might have to hustle, and a full pouch will make that a little uncomfortable.
As for the trip itself, just as a rule of thumb, and again this is a "me" policy, others might advise something else, but I generally keep one spare pouch/flange for every day I'm on the trip available. It's overkill, and I've never needed that many, but my thinking is it's better to have something on hand than have to try and find ostomy supplies overseas. As for disposing, I know Hollister supplies come with opaque bags. I keep those on hand, and just tie them up tight with the old pouch and place them in the garbage. Easy peasy :)
Hope that helps. I've rarely had any issues during travel. Be prepared for the trip and have what you need on hand, and it should be smooth sailing! :)