I used to be a flight attendant and gave up flying when I found out I was pregnant. I only did long haul flights and doing a lot of flying at high altitudes exposes you to too much radiation which can be harmful to your baby. Going on a few flights while you are pregnant should not cause a problem though, particularly if they're short haul, as it's very little exposure. You should try and walk about though to lower your risk of DVT but again the risk on a short flight like the one you would be taking shouldn't be too high.
Every airline does say something different about when you can fly until. With my airline it was 28 weeks or 34 with a dr's note. The main reason they say this though is they don't want to have to deliver your baby if it arrives early!
Hope this helps.
