Three of the coolest things I've seen aircraft wise in my life...
When I was younger, my grandma lived at our old family farm out in the Palouse wheat fields. The farm was situated in a low shallow valley with a gravel road leading to it about a mile long. When I was visiting in the summer and winter we would often hear flights from Fairchild AFB, and this was just before the USSR fell so it was still very active. One day I was out playing on the edge of the farm, which looked out over the long road. I was at the edge of the trees playing in the dirt, all of a sudden something appeared over the hills and caught my eye near the end of the road, and I saw two jets in close formation coming right at me, flying low and hauling ass. They were flying nap of the earth, probably a couple thousand feet high at most. There was no noise at first, and they came so quickly that all I heard was that sucking sound for a split second, the jets whizzed right above me, and I heard BOOM SSHHHHHHHhhhhhhh.. To a young 8-ish year old boy that was the coolest shit I had ever seen. Don't remember what kind of jets they were, probably F-15 or F-16, but to this day I remember that sight and sound vividly.
A few years back when I lived in Bremerton, I was out in the driveway one night unloading stuff from my vehicle, I heard the rumbling of multiple helicopters approaching, but couldn't see where they were. Suddenly four Blackhawks appeared, four of them in a diamond formation, with only the lead having its navigational lights on. They were flying so low that the bellies were lit by the ambient light from the orange street lights, and that was how I could see the three trailing Blackhawks that were running dark.
When we purchased our current place on Key Peninsula, I was out cutting brush and had a Kiowa pop up over the trees very low, guys sitting on the side doors with feet out on the skids. We also routinely have Apaches and stuff coming over, and a recently was surprised to see what appeared to be an Mi-8 - probably Polish or Romanian doing training with US Army, but couldn't make out the insignia.