I was on I-70 comming from St. Louis M.O on my way to Denver, I had never been to Kansas before so I was very interested in the scenery so my eyes were every where. I was heading west obviously and to my left I saw an object in the sky that at first I believed was some sort of kite, as I am studying it as well as getting closer, I reduced my speed from about 70 to 60, to notice that this was no kite because there are no strings attached to it and if it was a kite it was the biggest wierdest kite I had ever seen, and being from the beach thats saying something. I'm a little slow times and it all happened so fast, but anyways as soon as noticed there were no strings attached, it basically started going straight up higher into the air and started moving towards a big cloud, where it entered and vanished, it almost looked like it just took off going so fast no body would be-able to see it. Once this happened I started freaking out like no [cms/tg/pd] way did I just see that, started checking my rear views, looking back constantly not having a care in the world about wrecking, and nothing was in the sky but the clouds.....As far as the shape goes what checked if you put all those things together thats what I would say it looked like, like I said I thought it was a kite at first, but it's color was like a charcoal black/greyish color, it's hard for me to describe because it all happened to fast and I was basically in shock so yea, this is the first time I have ever seen anything I thought to be a UFO like for sure, I'v seen low flying planes before and thought was a UFO but then minutes later noticed it was just a plane. Hope this fiasco gets figured out in my lifetime....