Is a six-hour plane flight dangerous in early pregnancy?
Most people are concerned about changes in air pressure when flying during pregnancy. But in today's pressurized jet cabins, this is not a problem anymore. What concerns me is the fact that you will be flying for six hours. I have to assume that you'll be flying over water. (Hawaii? Europe?) The problem is that there's a 20-percent chance of miscarriage in any pregnancy. If anything like that were to happen to you in the sky—over water—your only medical care will be what's available on the plane ... almost nothing!
I've flown most of the major airlines and an airplane is not a very good hospital (nor should it be.) I've actually been the doctor when the loudspeaker has asked, "Is there a doctor on board?" It's not fun. (The equipment is so lacking on some planes that I now bring my own stethoscope when I fly.)
I would be hesitant about taking a long flight over land, but at least the plane will pass over a large city, a potential pit stop in an emergency, about every hour. But flying over water is taking a risk, not because of the pressure, but because of your distance from medical facilities.