The British government has approved plans for a third runway at Heathrow airport in London, at an estimated cost of Stg9 billion.
It will take 10 years to build.
Transport secretary Geoff Hoon says failing to boost capacity at Heathrow to match its European rivals will damage the British economy.
Mr Hoon says the airport is currently running at 99% capacity even though a fifth terminal was opened less than a year ago. Heathrow handles 65 million passengers a year and is the world's busiest international airport.
Airlines using the new runway will be required to use the newest, least-polluting aircraft.
The Conservative Party said the plan is incompatible with Britain's legally-binding commitment to cut carbon emissions.
If it wins the next general election, it will scrap the expansion and invest in high speed rail tracks instead.
Some 72,000 people work at Heathrow airport, which began operations in 1946.