unless there is complications I'm pretty sure it's 36 weeks ( if anything at all I'm sure some companies had no limitations on singular no complication pregnancies) - I was 32 odd weeks when I did Sydney to Bundaberg (and looked into it at the time and found I would have no problems) and even after complications while away they couldn't see me any problems flying home given they didn't expect I'd have nay further problems and their theory was it was faster than driving anyway