There is a website that has several different bird/airplane items that were discovered in South America. I do remember that an RC aeromodeler built models of them and they flew very well. I will try and find the lnk and post it.
What I find interesting, is that even though the models could be explained as being just items that were built from observation one would still need
a basic knowledge in aerodynamics with regads to lift and thrust. You can build a wooden model of a bird and throw it, chances are it wont fly. You
would have had to research which woods to use, how to curve the wing, where to place the wing & tail, etc.,etc.. Now knowing how curious humans are,
I would suspect that maybe there is a large size people carrying version somewhere, could this have something to do with the Ikarus legend? Just a