In a word - Xanax - or some other benzo. You don't necessarily even have to take it ... just having it with you may be enough.

I have anxiety also and I travel internationally. The anxiety on the front end of a trip is always there and I use a benzo when I need it. I don't imagine the anxiety will ever go away completely but it won't kill me either. Once I get home I am always glad I went and had the experience.

Bon Voyage!