Grey, silver triangular shaped flying object over Bonner Springs, Ks.Spotted a low flying triangular shaped vessel flying about 1000 feet off the ground. It was moving in a southerly direction and sounded similar to jet engines but as it went over me and I was struggling to get my phone out it was silent, I only heard the engine noise after it had passed and risen to about 1500 ft in altitude.The bottom was a flat gunmetal grey in color and completely triangle shaped but looked as if may have had panels of some sort. The thought that came to mind was like a piece of triangular paper had been folded accordion style and then stretched back out. The bottom looked smooth yet still had the visual accordion effect. It was about 200 yd from wing tip to wing tip. I could not get a picture of it.It traveled about 1/2 mile or so and then began a slow and controlled turn to an easterly direction. As it turned, I could see that the top was smooth and very shiny silver without the accordion effect of the underside. Shinier than an airplane and I could see no visible areas where it was welded or assembled. It looked like one piece of extremely high gloss metal. I was a machinist in the Navy, I have never seen such a smooth and shiny surface. There seemed to be some sort of cockpit of sorts near the front tip, maybe about 20 ft from the tip. I could not see any windows. I tried to chase it down to get a picture but it disappeared. It did not seem to be very deep as far as height.