I'm pretty sure AA will take international jumpseaters (in the cabin) but you probably won't be allowed in first class (filthy offline pilots anyway). You can also buy a ZED.

I have a buddy who flys UA widebodies SFO-Germany. Also Continental goes to Germany, if you have UA nonrev you should be able to go on CAL also (I think).

Lufthansa is very hospitable to offline pilots, I'm not sure if you can jumpseat on them but you can buy a ZED fare for sure. Unlike AA, they will put you in first class if there's room.

You have to check in with the gate agent, you're supposed to check in with the CA, and it's certainly nice to say hi to the lead FA (but don't ask her permission).