We are starting to discuss a family trip and my not-yet pregnant sister doesn't want to plan it for this summer saying she could be too pregnant during that time to fly. They have yet to start TTC. My mom thinks spring is too soon and fall would mean sister *could* have a newborn.

I'm rather annoyed since my parents were really looking forward to this trip and now it might get pushed back for a not-yet conceived baby. Even if she got pregnant next month she would only be 6-7 months in June.

What's the latest you've flown pregnant?