Hey Bec - we were in Vietnam just after spud was conceived, so there was a bit of travel there. No major problems with the flight except for the morning sickness and that bloody food tray being left for about 30 mins.
I flew to Queensland about 3 weeks ago (18-19 weeks?) I found I got really, really uncomfortable on the seats - my lower back got really sore, and I don't normally have a problem there. Getting up and walking around is a must.
I'm flying to NZ for Chrissie (26 weeks?). A bit nervous about this one even though its a short flight. I think I'll get really uncomfy on the plane so I'll end up standing when I can. I think I'll ask for an exit row for a bit more leg room.
My boss' wife flew to US and Europe at 12 ish weeks? She unfortunately developed DVT, a blood clot in her leg, spent a few days in hospital when she got back and was on daily injections INTO her tummy. Not nice! I have it on good authority she sat for the whole flight back, slept, and didn't move.
Just be sensible on the plane (water, moving around, exercises etc), and maybe take something to booster your back for the pains. Other than that - have a sensational holiday you lucky thing. Don't be afraid to tell the attendants too, they might look after you a little better.
Fi