[Mirek Wawrzynski]

Yes you are right. There are many wrong caption on the other side of photos, I have seen many of them too.

But much more probably would be the world "Polnische Flugzeug" not the "Flieger", this is only assumption? There were several cases when German planes had attacked also own plane (destroyed it), so the recognition was not very strong point among some airman. This cases were among Polish pilots too attacking/destroing own planes. Later in the war no problems, each side had such cases too.

mw