Black object flying toward clouds abruptly stop and then descend staight down and disappear.

I was driving my car eastbound on Golf Road approaching Arlington Heights Road in the city of Arlington Heights, IL, at approximately 4:00 p.m. when I observed what I thought was a plane in the distance flying toward the clouds.  
I was about to tell my kids to watch and see if they could spot it come back out of the clouds when the object stopped short of entering the cloud.  Knowing this was not possible for anything I know is currently being flown, I immediately asked my kids to look in the direction I was pointing and asked if they saw the black object in front of the cloud. 
Two of my 3 kids acknowledged seeing the black object.  As the traffic light changed I made a left turn and immediately pulled into a service drive to again be facing east. 
I still had the object in my sight as did my 13 year old daughter and 8 year old son. The object then began descending straight downward slowly and then disappeared. We stayed for a few minutes to see if it would reapp! ear but it did not.
I have watched aircraft my whole life and am good at judging distance. I would say this object was miles away judging by the size and distance of the clouds. Again the object appeared to be a plane because of the smooth straight line of travel it was taking but I could not see any distinguishing shape or trait other than it being black and shaped somewhat similar to an aircraft fuselage.