In a recent report Heathrow Airport was the preferred choice to have a third runway.
But how many runways does an international airport need?
Annual Passengers – City – Runways
22.7m – Atlanta – 5
21.6m – Beijing – 3
19.6m – Dubai – 2
18m – Tokyo – 4
16.4m – Los Angeles – 4
16.3m – Heathrow – 2
16.3m – Hong Kong – 2
Source: Barometer, The Spectator, 4 July 2015