Summer of 1962 Chicago "Plane towing lighted sign" flap

This sighting occurred in Chicago, IL in the summer of 1962 or 1963. I was 14 or 15 years old at the time and I was with two high school classmates. We were sitting on a park bench in the Sawyer elementary school playground. This is on the south side near 51st and Kedzie.
 It was summer vacation and we were out late (about 10 PM). It was already dark but as anyone who knows the city will tell you, the lights from the city will illuminate anything in the air. We noticed this object (which looked like a disk from our angle) move from our right to our left (this equates to south to north). It was fairly large and fairly close. I was about the size of a 474 jumbo jet and it was close enough to look like an airplane making a landing at nearby Midway Airport.
 It moved very slowly and there was no sound at all. As I said it looked like a disk from the angle we were viewing it at and it did not have sharp edges – they were more rounded. The edges had what looked like portholes (round windows) around the periphery of the object. The inside of the object was very brightly lit and it looked like people moving around behind those portholes! I remember seeing at least one “person” who appeared to be looking at the bird’s eye view of the city! I think the object was rotating but very slowly. Other than the light from the windows there were no other lights.
 We watched it slowly make its way very far north and we were able to follow its path until it just appeared as a spec of light which then moved east and disappeared. We were all very exited about this sighting and we decided to call the police to report it. It turned out that many, many people had called about this and the official police explanation was that it was an airplane towing an illuminated sign. I never believed that explanation because I know what I saw and it was NOT an airplane towing a sign.
 If anyone else saw this on that night in Chicago please tell what you saw. I would appreciate hearing that someone else was witness to this strange object (notice I did NOT call it a craft although I believe that is what it was). There is one person here who describes the same thing but with square windows and he says it was in September 1964. I am fairly certain that my date is correct – summer of 1962.
Witness indicates that the date of the incident is approximate.  PD