Croydon Airport: 100 years of air traffic control in the UK
The number of commercial flights rapidly increased after World War One, leading the British government demanding a way of managing the skies.
The first air traffic control tower was established inside a wooden hut at Croydon Airport in south London.
It became the world's busiest airport at the time, with a dozen flights to Paris and Brussels each day.
Now up to 8,000 flights cross UK airspace every day, which are managed by National Air Traffic Services.
Croydon Airport closed in 1959, but air traffic control is still essential for keeping the skies safe.