I used to believe that when you flushed the toilet on an airplane it would promptly exit the rear of the plane.
A childhood belief about aeroplanes

others believed things like this
- I used to believe that when you flushed an aeroplane toilet the waste would just drop out of the plane.Anon
- My friend's sister used to think the auto pilot on a plane was an inflatable man like the one in Airplane!— Richard Davies
- I used to believe that when you flushed on an airplane, it would land on the people below.Anon
- I used to believe that monsters lived in my toilet and they ate my poop and urine when i flushed the toilet.Anon
- I used to believe that if I flushed the toilet before I showered, I would take a shower in dirty toilet water.— Chris D
- I used to think if I left the toilet seat open my cat would get flushed down the toilet.— G