My OB told me the only concern with traveling is sitting for long periods, which can lead to blood clots. Apparently you are more prone to clots due to the hormones you are producing. So like a PP said get out and walk around every couple of hours. She also showed me some stretches and movements that can help prevent the clots, which are impossible for me to describe in text but you may be able to do a little internet searching and find them. Have fun on your trip!