(I have a couple of good ones backpacking involving aircraft)
Just a few of us pals during the summer when we were ~13. Hiked up the front of Squaw Peak mountain (I'm pretty sure you know which one that is) and over the top to a spot that was well frequented by many in the area.
Problem is, that's not the main trail so there was no warnings like there were down on the road up the backside to the trail stating it was closed off for exercises.
We get up over the top, start down this trail to the main area when all of the sudden three guys pop up out of nowhere fully armed, wearing makeup.
The one guys whispers pretty loudly at us to either get down or turn around and go back.
We were literally frozen in our tracks for a minute or so, scared to death.
It was shortly after Red Dawn had come out, so that was running through our minds.
We just sat down and hid. They came over and told us what was going on, and after they had disappeared back into the trees we high tailed it back over the front of the mountain.
Seriously, that scared me like nothing else ever has.
As for aircraft stories, I remember more than once being up in the mountains camping or on the hunt or something and having the sounds of a fighter jet of some sort go by with no warnings or no lights as well.