Large craft 2000 feet above ground

On January 20th 1989 I and two employees left my car dealership at approximately 6:00 pm southbound on route 45 in the town of Bourbonnais Illinois. We were in a large sedan. I was driving, one person in the front pass seat and the other behind me. Making a right turn westbound on Latham drive, a newly paved 4 lane road, I was talking to my friends and glanced to my left and noticed a large "something" above a K Mart shopping center approximately 1000 yards across a bean field. Being a private pilot I would estimate this thing at about 1500-2000 feet altitude. I immediately rolled down my window (electronically) for I thought there could be some kind of reflection. Not so. This structure, suspended in mid air was not aerodynamic and looked as it was a large building or even a group of buildings clustered together. I immediately commented to my friends "now what the is that?"  Both passengers with me noticed it and as I stopped the car on the side of the road it changed shape to a vertical cigar shape and looked to us as if it was going to crash right in to our immediate area, causing one of the passengers to scream. It moved towards us at an unbelievable rate of speed. It then changed back to the shape it was in (cluster of buildings) right above us. Dusk was changing to dark. There were many (6 or 7) small ships flying around this large ship at no particular pattern. Again I can not stress how big this thing was. I am from the Chicago area and it was for sure as big probably bigger than the sears tower downtown Chicago. Above us it moved slowly to the northwest, maybe one or two mile an hour for 500 yards. While directly underneath the ship we noticed three large circular lights or burners ignite with the highest intensity bright white light I’d ever seen. At that time the ship started to slowly become transparent meaning we could start to see through it until it had completely disappeared. Note as it disappeared it did not diminish in size.