It's quite obviously fake, the real question is who made it and why? It's a good movie I guess, but what strikes me is that, while it's obviously well made, why do the people that make these always assume that any aliens are showing off their ship? It makes no sense for these, supposedly, intergalactic vessels to slowly hover 50 meters over an island.
A bit less technical brawn and a bit more common sense and the believability factor increases tenfold.