The blogger at your link should have been clearer on the origin of the stock shot, and a bit better organized. The original photo is from http://www.ishilab.net/~ishihara/blog/media/1/, and is seen below:

I do not know if the photo originated with the owner of that site (it isn't in English) or somewhere else.

This is the UFO photo:

Making a picture like this pass a digital test is easy. You can crunch it through the pixel altering process enough to blur almost anything, including artifacts. Essentially, you convert the picture into a single, giant artifact. Of course, you can also print out your hoax picture, and with enough skill, simply photograph it with your cell phone.

On the other hand...

I did my own overlay, and noticed a couple of things:

The angles of the two photos are quite different, and a lot of tilting is necessary to match them. The UFO in the photo is actually off the margin of the stock picture, and someone would have had to create new background to match it. Not impossible, but no piece of cake, either. Nor, as the morph shows, do the lights in the distance match, and erasing those seems a bit weird. The exact match for the runway lights is not surprising. They never change. I noticed other things that would have to have been done to the photo to come up with the final that would also be difficult, like removing the planes. In addition, the lighting conditions of the sky are completely different, with one typical of a clear sky as dusk or dawn, and the other typical of overcast, with a range of brightness from top to bottom.

If one were going to do a hoax, why not start with a different obscure stock photo and simply lay the UFO in without having to alter all the rest of the picture?

I'm speaking as someone who makes a living, among other things, plugging artificial things into background shots and having to make it look like it was really there. If I ever decided to start farming out UFO photos, I'd be famous.

I'm cutting the UFO nuts some slack on this one, and stating that it is just as likely that this was two different pictures taken from a fixed observation point at the airport (my local international airport has only one small balcony where you can go outside to watch planes take off and land). This does not mean that the UFO picture is not a hoax, simply that it is probably not a processed version of that particular stock shot.

I didn't see the second photo on Lindy's link (below) at the Wikipedia site. Did I miss it, or has something been changed in Lindy's link?