What about police helicopters, which are out every night for hours at a time.
They are very very loud and will wake you up from even a deep sleep.
They are very very loud and will wake you up from even a deep sleep.
Edit: After googling, it looks like there are about 2000 police helicopters in the US, but only 20 in the UK. As far as I can tell, there are the same number of police helicopters in LA as across the whole of the UK.
They make use of helicopters typically before a car arrives.