Proved that it's fake? Look at the colors/levels in the image. Anyone who's ever opened Lightroom or Photoshop would immediately tell that this has been processed and not subtly at all.
Another thing is that photoshopping planes like that for a "crazy timing" effect... Is exactly that, the OP isn't trying to hide that this is real, it's obvious that it's not, based on composition.
The ridiculous thing is when people outside of photography communities think that some collage is real and go around trying to prove that it's not.