Unlike most airports, London's Heathrow is privately owned, so it's a great case study for how airports make money. Wendover Productions explains.
Soon, this airport will be making even more money. This summer, Heathrow got approval to expand:
In terms of passenger numbers, a third runway could increase capacity to 130 million, two-thirds more than the 78 million who passed through Heathrow last year.
The Department for Transport says the expansion will bring more jobs and greater economic growth along with more flights: "A new runway at Heathrow would provide benefits of up to £74bn to passengers and the wider economy and create tens of thousands of local jobs.
"It will better connect the UK to the rest of world with an extra 16 million long-haul seats available by 2040."
• How Airports Make Money (YouTube / Wendover Productions)