I second (or third?) talking to your doctor. We went to the Caribbean when I was 30 weeks and my midwife gave me the okay to fly until 35 weeks. But she said if there were any complications before the trip we would have to cancel. Make sure your insurance would cover any emergency doctor visits where you're going and get information on the consulate there (phone number etc) just in case baby comes early. You should be fine, but it doesn't hurt to be prepared
You need to first speak to your doctor who will probably prescribe some kind of anti pressure stockings and you would also be given some medicine or shot ( in Germany they do). Beside your doctor, the airline would require some documentation from you and will inform you about their cut off date. So if I was you, I would first check with airlines, find out what all is needed then call my doctor
The only one who can answer that is you and your doctor