Abnormally bright white light stationed in the sky approached by aircraft.

After spending the day romping in La Verkin Creek in the backcountry of Zion National Park, my girlfriend and I noticed an extremely bright white light stationed about 10-15 degrees above the horizon on our walk back to our campsite.  The light was much wider in diameter than a typical star (perhaps 5 times as wide) and much brighter.  The light appeared to be somewhat far from us as it was way out on the horizon.
After a few moments of staring at the light trying to figure out what it was, both my girlfriend and I started to feel a strange energy in the air (that of a presence), and everything felt exceptionally quiet and still.  Within a few minutes, we started to notice an aircraft flying directly toward the light.  The aircraft was sleeker than a commercial aircraft so it was my guess that it was a military aircraft.  That hypothesis was reinforced when the aircraft slowed down to almost a complete stop as it was approaching the light, something that I think would be atypical of a commercial aircraft.  After that airplane arrived, we noticed helicopters approaching in the distance.  I have to admit that the energy that we felt coupled with the approaching aircrafts made my girlfriend and I pretty uneasy as it felt like something big was about to happen.
This whole time the light did not move in any direction, but it did have a slight pulse to it with a period of a few seconds.  During that time the light went from bright to slightly brighter and slightly larger and then back again.
After about 5-10 minutes of very still, tense energy, the white light disappeared.  The way in which it disappeared is kind of difficult to explain.  It appeared to get smaller and fade in brightness until it completely vanished.  It was almost as if it flew into the distance at an extremely fast rate.  For this to have been the case, it would have been flying further toward the horizon and the opposite direction of where we were.  The disappearance of the light took approximately two seconds.  After that the energy subsided and the aircraft left the area.