>>53983685size is one of the few things in the universe that is absolute, not relative.
wings are effectively 2D
but birds themselves are 3D, so they don't scale up the same.
Just about the closest things are the gigantic prehistoric birds (argentavis, pelagornis, etc etc)
and the fact that, while you can't really have a house sized bird, you could have a tiny human (think like a foot and a half in height and light enough to carry with one hand)
and large (like the size of a large eagle) birds, and that difference actually would be enough that such a person could fly on such a bird.
But we already know how shit life is.
