From the BBC.
Note the third runway is manned to add the following capacity:
A) headroom for 50% more flights pa (even I had worked this out)
B) 75% increase in passenger numbers (don’t know how this works - bigger planes?)
How does any of that mean less time spent in the air - an extra 240000 flights just as prone to delays caused by fog or service issues on the ground?
How would Heathrow Airport be expanded?
Heathrow is already the UK's busiest airport, serving more than 80 million travellers a year with its four passenger terminals and two runways.
A third runway would mean demolishing hundreds of homes, diverting rivers, and rerouting the M25 motorway between junctions 14 and 15 through a tunnel under the new runway.
The number of flights, currently capped at 480,000 a year, could go up to 720,000 - or nearly 2,000 a day on average.
Heathrow told the BBC that it would eventually be able to serve up to 140 million passengers a year once the third runway is in operation.