D.K.
I agree about bottled water. It'll be easier to lug around if you get yourself one of those camelback things and fill it up with the bottled water. You can wear it on your back and sip from it all day. It'll hold about a gallon depending on which size you get. Use it for everything, even brushing your teeth. Like the other posters said, don't even get ice-cubes in your drinks. Stick to something familiar when ordering drinks, like coca-cola (not usually the best when preggo, but better than Montezuma's Revenge - a.k.a. bacterial diarrhea from drinking the water). And really, just sticking with your water is probably the way to go.
I also agree about taking a body pillow on the plane. A 6 hour flight shouldn't be too bad. Just make sure to get up and move around.
Also, don't forget the hand sanitizer (Bath and Body Works has some that smell AMAZING and are small enough to get through security with).
Wear comfortable shoes. Forget the heels. I don't care what line of work you're in, no one is going to be offended by a pregnant woman wearing a nice, clean pair of sneakers with her pantsuit or skirt instead of heels.
Make sure you carry something with you that smells good. I recommend a small vial of aromtherapy oils in vanilla or lavendar hung around the neck and easily accessible at all times. Both are calming and they will give you something to hold under your nose when you encounter the inevitable bad smells. You don't want to be throwing up in a strange place. It'll make you seem vulnerable and it's not comfortable.
Wear loose and breezy maternity clothes if you can. It's going to be hot so you'll have to work to stay cool and comfortable. I'd also recommend taking unscented baby powder with you. You can use this in all of the places that rub to make sure you don't break out in a heat rash.
Consider taking a small, personal fan with spare batteries and keeping it in your handbag once you get there so it's always available in case you start to get overheated.
Definitely agree that you should have emergency plans in place and coordinated with a loved one here in the states. Make sure you have the number and address of the local hospitals with you at all times. Also don't forget to take your own OBGYN's number with you to give to any doctor that may need to treat you while you are there. Make sure to have a list of any conditions you have and keep it in your wallet. It's the first place anyone would look for medical and identification information.
Well, that's all I can think of, but I'm sure you'll get lots of great suggestions.