Tulpas

Bigfoots and Loch Ness Monsters are very likely results of tulpas.

When lot of people believed it's real, it became real then there are sightings.

Once less of people believed in them, it faded away, less sightings.

It's also called thoughtform.

Bigfoots and Loch Ness Monsters are not only things that created by thought. There are several more creatures out there that are scary or normal or whateverso.

Here are several links for you to read.

http://www.davisanddavis.org/harvey/tulpa.html
http://en.wikipedia.org/wiki/Tulpa
http://en.wikipedia.org/wiki/Thoughtform
http://www.mystae.com/restricted/streams/scripts/tulpas.html

More on Military UFO

scene from X-Files show "Dreamland"

As seen in the show, the government has made a aircraft that resembled as Belgium UFO. In sense it is smaller than Belgium UFO.

There are some reports on that near Area 51 and other places. This image I found is good example of what our government can do.

Unfortunately, it won't be as advance as original out-of-worldly aircraft. It can be either unmanned or just one man craft compare to unknown aircraft that carried hundred aliens.