Heathrow expansion: Plane spotters take 'blind test'
The decision is still pending on whether a new runway will be built at Heathrow or Gatwick to try to meet the UK's air capacity needs.
But many people living near airports fear any expansion would make the noise from landing and take-offs worse. The airline industry argues noise can be minimised with modern aircraft design.
In a very unscientific study, video journalist Dougal Shaw visited a spot popular with plane spotters near Heathrow, to see how distinctive plane noise can be.
He asked Keith Blackham, Brian Richards and Peter Harding to guess what make and model of planes were landing behind them, without seeing them.
Read more about the environmental factors affecting airport expansion here.
Find out what it is like to live near Heathrow in this article.