2012-06-02 - Chicago, IL - Rectangle

Large grayish rectangle outlined in the sky

I was driving with my wife mid-afternoon on June 2, 2012, eastbound on I-90 Kennedy Expressway in Chicago. I had passed O'Hare a couple miles back, when I noticed a rectangle in the NE sky similar to a drive-in movie screen.

At first I thought it was a new billboard and then I realized it was way far in the distance and very high in the sky, about 45 to 50 degrees above horizontal. There was no visible support for the rectangle and the sky out over Lake Michigan was only slightly hazy.

I was about to point it out to my wife when traffic and buildings obscured my view for a quarter mile or so, and I was never able to catch sight of it again.

I am a pilot and post this as a matter of interest. I realize there is at least one possible explanation, that of an aircraft towing a banner. Although this did not appear to be what I saw.