Vacation to Germany Everyday life and customs

I plan on taking my first out of country trip to Germany this coming summer, to stay with a friend who was an exchange student at my school!
I have never been outside of the U.S. and have never been on a commercial sized airplane!!!! Any tips, tricks, rules, or customs I should know about?
Thanks!

Soon ;DDDDD

You mean for the airplane kerp mouth sometimes open that the air gets out
And for germany...which city do you actually visit?

When I was in America I stumbled upon quite some people mocking Hitler or re-enact his poses when I mentioned that I speak German. It was all a 'joke' in America, but it's actually illegal and one of the fastest ways to get yourself fined and hated in Germany 🙂 On social-cultural level, Germans (and Dutch people as well) tend to be slightly more reserved compared to Americans, but nonetheless a great and sociable people 🙂