I would love to have an aircraft profile database on this website where I can search for my favourite profile and download it.

Of course these have to be provided "as is" with no warranty

You just posted in it.

Actually, i was thinking of a Website with listboxes, where I can select a manufacturer, then one of the models and then get a file with teh aircarft profile presented for download.
Of course a Feature is needed to upload the user-made profiles. I know that Skydemon is  not able to provide (proven) profiles for every aircraft type and model