I am looking into going back to the Christmas markets next year, but this time I am thinking of leaving from Prague. There doesn't seem to be any direct flights to the US from Prague, and instead I will have to go through Frankfurt.
My question is, how does that work as far as customs, security, etc.? Am I going to have to go through all of that in Frankfurt, then once again in the US? And the flight I'm looking at only has a 1 hour, 40 minute layover in Frankfurt. I don't know if that will be enough if I do have to go through all of that.