I was driving westbound on Interstate 435 and noticed 3 triangles floating from south to north.They were not all in the same line. Seems like the middle one was a little higher. They were transparent but you could see through them like a reflection in rippling water. I did see something that day and have not seen anything since. I was watching the History channel and Hangar 1 was on so I thought I would let you know. I remember it was around 1989. Not much sooner or later. It was and is still hard to explain. It would have been easy to not see.