Amazing footage of UFO flying past commercial plane.

The amazing footage was shot by a passenger on a commercial flight over Spain. 

You can see the diamond shaped craft flying under the plane. The interesting part is when the craft seems to speed up and accelerate away. 

An amazing detailed diamond shaped UFO

The comments on the video that was uploaded by Section 51 2.0, were mostly positive with only a couple of people claiming it was just a weather balloon.
The most interesting comment came from what seemed to be an experienced UFO enthusiast, he commented:

“Excellent. Not fake.. the tricky part of adding an image from a camera phone.. is the perspective and speed.. this passed the test of enlargement.. and quite detailed.. it’s speed was probably 2-3 times that of the airliner.. which indicates they want to be seen”.

What do you guys think? Is it too good to be true and a fake? Of is it an amazing piece of UFO evidence?

Source – Section 51 2.0 / YouTube