Hi Elizabeth,
It sucks having to cancel planned trips due to preggie, but it's worth it I guess. My doctor says best to avoid air travel during first three months. Apart from the fragility of our health during the first three months, it is also the period when most of the organs of baby are forming. Supposedly (and I heard more than 1 doctor say this), due to radiation when flying, it's not so good because radiation can cause minor mutations. At such an early stage of baby forming, very minor mutations can cause big consequences. So best to avoid. I'm holding off my trips till mid December when I'm into second trimester. Sad sad, coz hubby away every other week and I want to follow him but cannot.