They Don't Know What They're Singing

Did you think that the words of the title Chitty Chitty Bang Bang refered to the noise that the car made?

WRONG.

"The name of the car was not derived from the sound it made, despite what Hollywood would have us think, but from the words of a bawdy first world war soldier's song. Officers would obtain a week-end pass or chit so they could go off to Paris for a couple of days and enjoy the favours of the ladies of the town at their leisure. Chitty chitty - bang bang."