I just wondered if anyone can tell me when it is safe to fly when pregnant and how often?

I had heard that it was about 36 weeks for short haul flights (which is the ones I do). The thing that concerns me is that my boss is currently booking more and more trips interstate for me to do before I go on maternity leave (which I have said will be at about 38 weeks) it's like they want that last pound of flesh before I go on leave.

It's getting me down a bit because I said I would stay until 38 weeks as a favour to them and now they are pushing me harder than ever before. I can usually handle a fair bit of stress but don't see why I should when I am pregnant. Trouble is, they are dangling the carrot of the possibility of working from home (Don't know if this will happen), once bub is born so I feel like I am between a rock and a hard place.

I don't want to be doing all of this flying if it is harmful.