UFO Sighting in Chicago, Illinois on 2017-06-08 18:45:00 - From a plane, i saw a short dark vertical line that rotated to horizontal, disappeared and reappeared, above a much larger horizontal dark line/shadow on top of clouds that did not move

We flew out of ohare airport to atlanta on thursday, june 8. at 6:45pm local time, approx 15 mins into the flight, at cruising altitude, i looked out of the left side of the plane and backwards -- so looking in a nne direction at about the same altitude as the plane. i saw a long dark, horizontal cloud or shadow on top of the clouds and above it and to the right was a short vertical black line. as i watched, the short vertical black line started to tip to the right, and within 30 seconds it was at 45 degrees. i scrambled for my phone to take a photo. attached is the photo and a screen capture of the area zoomed in. i continued watching. from 45 degrees the black line went to horizontal, then disappeared. all of that took about 2 minutes. i kept watching. then, about 3 mins later, the horizontal black line was back. it started to lengthen, to about 4 times its original length, then disappeared. throughout the entire episode, the long dark, horizontal cloud or shadow below this did not change. i looked up to see if there was anything that could be making a shadow and did not see anything. way off in the distance, to the north, i could see 2-3 more of these long dark, horizontal clouds or shadows. i don't think they are in the photo. as the plane continued to travel away from the phenomena, eventually i was too far away to see anything more.