Lynda, ahh plane travel...how not to panic?!!! It sounds to me like you are prepared, do take those meds, but I find it useful to take a relaxation tape with me so that I can block out what is going on (and pretend I am anywhere else).
Do you have any breathing techniques or tapes that help you out? I would take as much arsenal with you, books, dvd's etc that will distract you. Remember, even if you have an anxiety attack, (that sounds negative doesn't it?) it will pass and you will get where you need to be. I wish you all the best, please let us know how you are doing okay?
Panic Attack Survivor
Weekend Warrior Princess