For example:

https://www.dw.com/en/ufos-and-aliens-in-germany/a-58077707

However at least of the German UFO clubs seem to be perfectly reasonable:

In Germany, there seems to be an endless list of hobby clubs and nonprofit associations. The Association for UFO Research (GEP) is one of them. Their databank includes 140,000 entries, and 95% of them can be explained. Aside from satellites, strangely shaped balloons is one common answer, as well as weather phenomena and insects that zoom across photos. The remaining 5% "perhaps also have natural causes, which we just can't explain yet," Hans-Werner Peiniger, GEP's head, told DW. Members of Germany's UFO clubs — there are at least three — are not blind alien believers, Leipzig-based Fleischer said. They are rational, engineer types who use limited resources to analyze what curious sky watchers send them. The result, however, can be a great deal of information about what is happening above us. The really interesting cases "are a matter for the military," Fleischer said. "They control the skies and have instruments and radar."