This very short video looks staged to me. But, it does show a good shot of a jeep with “MESSENGER” written across the windshield.

“An American Messenger jeep drives up road past soldiers. Various shots as they take carrier pigeons out of basket. C/U swastika on paper tied to pigeon’s wing. C/U message American soldier is writing ‘Adolph (sic) Hitler, Berchtesgaden. No Happy Returns on your birthday but see you soon. Ninth U.S. army.’ Various shots as they tie message to the pigeon’s leg and release it. We see various takes of the same scene.”