I thought the lines in the sky left behind by airplanes were "sky scrapers". Makes sense.
A childhood belief about aeroplanes

others believed things like this
- I used to think that the trails that Airplanes left in the sky, that's how clouds were made.Anon
- My nephew, at around age three, used to say that airplanes trailing white exhaust were "airplanes on strings".— Mojo!
- I thought a major general is more powerful than just a general (which still kind of makes sense to me)— Demond
- when i was little, i used to believe that airplanes goes out of space.Anon
- When I was little, I used to believe that airplanes took off like rockets.— Edene
- I used to believe airplanes were flying submarines.— Gullible isn't in the dictionary