I think you need to ask your ob or GP about this one. I know in second trimester - after 13 weeks or so - it's generally ok, but I seem to recall once reading something about flying being linked to miscarriage in first trimester. On the other hand, the flights you're talking about are really quite short so maybe that's OK. I flew to cape town and back when 21 and 26 weeks pregnant; i think my ob had me take half an aspirin before each flight and told me to make sure I walk around the plane a lot.

it'd be a shame to miss your holiday! hope you don't have to.