Sounds like you've done your research! Definitely take double what you think you need. And remember, they have pharmacies down there so you can buy things you forget.
For plane travel, put the juice in a ziploc bag with the insulin and syringes, etc. Alex gets his juice thru every time (but usually 1 out of the 7 or so TSA people you see will say something about it and then be overridden by the others). But if you can't get it thru, don't fret. You can buy juice on the other side of security! Definitely plan to buy water on the other side or bring empty water containers and fill them at the water fountain (buying new is more expensive but maybe safer, germ-wise). Take along some skittles or other candy he likes just in case you are out of juice and need something.
For syringe disposal, I'd take along a small syringe disposal container. You can get them at drug stores. That will be safer for the housekeepers, etc.
Just plan to test a little more often and don't freak out if he runs a bit high for the trip. It's hard to keep up with bgs when they are excited (maybe runs them higher) and then overly active (makes them go lower) and eating all sorts of food that you aren't sure about carbs with. And have fun!
Barbie, Mom to Alex, 20, dx 10/05, minimed pump 10/06, dexcom 8/10