I used to believe that after you went to the bathroom in an airplane, a hatch would open up in the bottom of the plane and dump the waste out into the air.
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 think that when sombady when to the bathroom in the plane it would go strait out and fall on sombody— Tony Magana
- I used to believe that all animals hatch from eggs— Bryan Flores
- I used to believe that you could keep a chicken egg (that you bought) warm, and it would hatch!Anon
- Lightning and thunder were produced at the garbage dump.— penny