Flying above highway 401 during rush hour it was going east above the lights

I thought it was a bird but it flew seamlessly. Then I thought it must be a drone. As it got closer I couldn’t understand what it was. Then I thought maybe it’s a plastic bag blown by the wind. There was no wind and this seemed to move controllably.
I figured once it flys by, I can see what type of drone it is, as it flew by there was no backing, only a small hump at the back. The only item I could compare it too was that of a dinner plate, but flying horizontally but in a vertical position. I was driving west, this was flying east, above the highway. I didn’t record a video and I kept making rational excuses that this was a man made drone.