I thought that the white vapour trail that planes leave behind them was actually from special 'weather planes' sent up to make the smoky trail so that weather forecasters could observe the trail and forecast the weather for tomorrow. (My husband only recently cleared this up for me!)
A childhood belief about aeroplanes

others believed things like this
- I thought weather forecasters were psychic and that's how they knew what the weather would be.Anon
- I thought that Indian Summer was like the weather in India.Anon
- i was scared to fart outside in cold weather because i thought u would be able to see the steam.— xJeNneSceNcEx
- When I was very young, I thought that God was married to Mother Nature, and that together they made weather.Anon
- I used to believe that I could control the weather... I had limited success— Mark
- I used to be very fascinated by the weather and sometimes wished I could have a tornado for a best friend.— Will