Originally Posted by
Kilianerz
This is my first time here by the way. So I'm trying to fly back to Germany with my 2 year expired passport. I have a US green card that is now expired for about 2 years now and is also missing.
So no resident permit and no passport!? That's going to bode well with CBP...
Let's just say that you'll probably won't be able to return to the US in the foreseeable time.
BTW: Without any form of ID allowing travel to Germany it's also highly likely that you won't make it as far as the TSA. Airlines departing the US will have to collect data on behalf of the CBP (data you're not able to provide if you don't a valid travel document) and airlines will check your travel documents against their database to check if you can enter Germany. In doubt, they'll just cancel your check-in.
PS: Your best course of action is probably to contact the German embassy in the US and apply for a new passport. That still might not resolve your potential trouble with CBP.