Xanax to prevent anxiety while flying.

Patient: Hello, my name is Megan I was given an RX for .5 Xanax in march to calm me down (had a previous panic attack while flying) while I went on a airplane trip. My Rx is still vaild and I still have several pills left plus and unfilled refill. Im 18 weeks pregnant and need to take another airplane ride in a month. I would ask my obgyn about this, but am in the process of find a new one who has more time for me. I was wondering if I take a pill or two during the 11 hour each way trip… does the put my baby at risk ? Thank you so much.