According to that link you posted, there are two meanings to AWACS, one to indicate the general principle and one to indicate the Boeing/Westinghouse system which is exclusively deployed by America and Japan.
I doubt that it was a Japanese plane in use there (though theoretically it could be).
The F117 is exclusively operated by the US air force.
Interesting, I never knew that. The Geilenkirchen airforce base is about 3 Km from my house, I can see the AWACS planes take off with some regularity, all of them have American markings.
I went for a walk in a British one at the Abbotsford Airshow this summer (all UK crew), and I know the NATO ones can have Canadian pilots and Radar ops.
The US does operate the E-3's as a part of their Air Force as well, but the NATO ones are not American.
Interesting. I'll see if I can catch one on camera, the wind has to be right for them to take off in this direction and it is night right now but it happens with some regularity.
There are lots of interesting craft here, not just AWACS.
Google maps has the area 'obfuscated', so I can't use that to look at the planes (it was to be expected), but I'm sure an opportunity will come soon enough.
edit: this side of the border there is actually quite a bit of resistance against the AWACS craft taking off and landing because they are technically in Germany but the noise pollution is mostly felt on the dutch side which is much more densely inhabited than the German one.
I doubt that it was a Japanese plane in use there (though theoretically it could be).
The F117 is exclusively operated by the US air force.