How much cash can I carry on a flight? I'm worried now.?

should not be a problem.When I traveled in europe, at no time did anyone ask to see the contents of my wallet. When traveling overseas, one cannot carry more than 10,000 dollars US. I would also advise you not to tell people at the airport that you are carry that much money. I agree that money orders or cashiers checks or travelers checks of some sort are your best options.