2019-09-11 - Chicago, IL - Sphere

I was on a commercial jet on final approach into Midway airport near Chicago. We were Over Lake Michigan at approximately 1k feet and I saw what I thought was a white bird Like a seagull flying above the water going in the opposite direction as the plane. As it got closer I noticed that it was not a bird but rather a white ball shaped object flying at a steady rate. There were no propellers or any type of exhaust or thrust producing mechanisms. It just moved under the plane at a steady rate. It’s difficult to determine an exact size because it was below me and appeared by be ~ 20 fee above the water. If I Were to guess I would say 2-3 ft. in diameter. I have never see a UFO in my life, I’m not sure what this was but it was very strange. No one else on the plane made a comment that I could hear.