I used to love going on planes as a kid so I asked why we don't ride planes more often and my mom told me that it's very expensive. I was her newspaper coupon-clipper so with a solid grasp of money I asked how much I remember she said "$2000". I remember being astounded... to an 8 year old anything bigger than $100 was utterly astronomical.
I'm ashamed to admit that well into my mid-twenties I was under the belief that typical plane tickets costed thousands and thousands of dollars.
A childhood belief about aeroplanes

others believed things like this
- I thought that the jetstream from planes was white paint. Which was constantly poured out from the plane.— Tore
- i used to believe that planes did not fly the ground just moved.— bob the pinecreek
- I used to think that planes were held up by stringsAnon
- i believed like when i was 3 yrs. old i thought that air planes would come to your house to pick you up!— Brooke
- I used to believe planes flew by being attached by strings like a kite.Anon
- I believed that Jesus was flying across the sky, it was actually sunlight reflecting off planes.— Patti