I can't imagine why flying for an hour would be a problem. You regularly sit for an hour, no doubt, on most days. (Of course I don't know your medical history or anything - maybe there is a good reason, and you got to do what the doctor says of course)

I flew from Melbourne to Hong Kong to Osaka and back when i was 6 weeks pregnant. No problems with the flight, though MS started in Japan, which wasn't much fun at all. I just made sure to drink lots of water during, before, and after the flight, and to get up and walk around from time to time, as I always do.