Originally Posted by IO540
This whole business of mid-air risk is massively overdone.
Apart from close to airfields (e.g. the Stapleford/Wellesbourne sunny Sunday free for all
) it is as close to zero as one can get. In an aircraft with infinite endurance, etc, you could fly on random trajectories, above the MSA obviously, blindfold, and it is 99% sure you would die of old age before hitting something.
Oh, you've done the sums have you? What's the mean free path then? - I didn't know anyone had actually done the arithmetic!
(Sounds like a question for what used to be the whacky physics paper in the Cambridge entrance exam. Optional paper, full of daft questions like this where you're given no data and have to guess all the parameters; lots of brownie points if you give good answers, no penalties for making a complete cock-up of the entire paper.)