Here is a timeline of some of the key events in the debate over expansion of airport capacity.
It is reported that Labour ministers are "seriously considering" building a runway at Heathrow in order to keep pace with other European airports.
Options for UK airport expansion to meet the expected demand for air travel over the next 30 years are outlined by the Labour government. They include a third runway at Heathrow, a new four-runway airport near the River Thames in Cliffe, north Kent and up to three new runways at Stansted. Transport secretary Alistair Darling stresses that doing nothing is "not an option" as existing capacity will not meet demand.
The go-ahead for a second runway at Stansted by 2011 is given by the government, followed by a third runway and sixth terminal at Heathrow by 2020 if strict limits on noise and air quality levels are met.A Government White Paper rules out a new runway at Gatwick until at least 2019 due to a non-expansion agreement.
The government reaffirms its backing for two new south-east England runways. A progress report on the 2003 White Paper confirms that a sixth terminal will be required at an expanded Heathrow. Transport secretary Douglas Alexander says a new runway at Stansted will not be operational before 2015.
Protesters opposed to the aviation industry and Heathrow expansion set up a Camp for Climate Action near Sipson on the northern edge of the airport.Police and demonstrators are involved in a number of skirmishes but fears of mass disorder during the 10-day camp prove unfounded.
The government outlines proposals for a third runway and sixth terminal at Heathrow. The new runway to the north of the airport will be longer than originally envisaged and could be in operation by 2020. A third runway could be built while meeting noise and air quality targets, the government says. Launching the proposals, transport secretary Ruth Kelly says that if nothing changes, Heathrow's status as a world-class airport will be "gradually eroded".
Climate change protesters climb on to the roof of the Houses of Parliament to demonstrate against the expansion of Heathrow. The five activists from campaign group Plane Stupid unfurl two huge banners over the historic building and remain on the roof for three hours before being arrested.
Heathrow's new £4.3 billion Terminal Five suffers a disastrous opening day with flights cancelled, luggage delayed and long queues. Tory leader David Cameron says the "humiliating" launch could hamper the case for further expansion at the airport. "Recent events don't exactly strengthen the case," he adds.
Opposition party the Conservatives promise to scrap plans for a third runway at Heathrow and opt instead for a high-speed rail network linking Leeds, Manchester, Birmingham and London.
The decision on expanding Heathrow is postponed by the government amid speculation the cabinet is split on the controversial plans.
Labour backs a third runway despite strong opposition. The #9 billion project gets the go-ahead after prime minister Gordon Brown says the needs of the economy and the environment have to be balanced.The government faces fierce protests, not only from local residents, environmental groups and local councils but also from Labour backbenchers.
Conservatives and Liberal Democrats are also against expansion.The decision supports the building of a third runway likely to be completed by about 2019/20.
London mayor Boris Johnson and a team of engineers sail into the Thames Estuary in search of a possible site for a new airport. He says the proposal to build an airport on an artificial island in the estuary could be a viable alternative to Heathrow.
David Cameron tells a public meeting in Richmond, south-west London, that Heathrow expansion will not go ahead, saying "no ifs, no buts".
Following a general election, the new coalition government immediately scraps plans for a third runway at Heathrow, reflecting manifesto promises of both the Conservative and Liberal Democrat parties. Extra runways at Stansted and Gatwick are also ruled out.
Both prime minister David Cameron and chancellor George Osborne acknowledge the need for airport expansion in south-east England.It is reported that they are prepared to look again at options for Heathrow, in a move set to anger their Lib Dem coalition partners and Tory MPs in west London.
An independent commission on future airport policy is set up by Whitehall.It will be chaired by Sir Howard Davies and will publish its final report in the summer of 2015.
David Cameron tells the House of Commons that he will not break his manifesto pledge ruling out a third runway at Heathrow during this Parliament, but adds that a decision is needed amid growing business clamour for more flights.
Justine Greening, who is against Heathrow expansion, is replaced as transport secretary by Patrick McLoughlin.
Politicians are likely to have to decide between a new runway at either Heathrow or Gatwick, following an interim report by the Airports Commission.
Sir Howard Davies's commission concludes there is a need for one net additional runway to be in operation in the South East by 2030.His team will now carry out a detailed study of proposals for an extra runway at Gatwick and Heathrow, as well as extension of an existing runway at the latter.
Expansion at Stansted is ruled out until after 2030 but the door is not closed on a Thames Estuary scheme favoured by Boris Johnson.
The bosses of Heathrow and Gatwick outline their revised plans in submissions to the Airports Commission.
Heathrow envisages a third runway built by 2025 that would see the number of annual flights at the airport increase from 472,000 to 740,000 by around 2030.
Gatwick says that its plan for a second runway will lead to an extra 260,000 flights a year by 2050 compared with the current 248,000 a year.
The "Boris Island" Thames Estuary airport plan is officially rejected by the Airports Commission.
The scheme, championed by Boris Johnson, is ruled out after the commission says the proposal has "substantial disadvantages that collectively outweigh its potential benefits".
The long-awaited report by the Airports Commission recommends that a new runway should be built at Heathrow rather than Gatwick.
The commission says expansion would generate up to £147 billion in economic output over 60 years and create more than 70,000 jobs by 2050.
It recommends a "comprehensive" package of measures to make Heathrow's expansion more acceptable to the local community, including a ban on night flights from 11.30pm to 6am and legally binding limits on noise.
Gatwick is unlikely to provide urgently needed capacity on long-haul destinations, according to the report.
David Cameron says "the guarantee I can give" is that a decision on expansion will be made by the end of the year.
Patrick McLoughlin announces that a final decision has been put off until at least next summer "subject to further consideration on environmental impacts and the best possible mitigation measures".
He says there is a "clear" case for airport expansion "but it's vitally important we get the decision right".
David Cameron resigns following victory for the Brexit campaign in the EU referendum, leaving the decision on airport expansion for his successor Theresa May.
Transport Secretary Chris Grayling confirms that the Government's decision will be made by a cabinet sub-committee on October 25.
Downing Street says that under a special arrangement, ministers opposed to the outcome will be allowed to express their "personal views" for a limited period.
Gatwick insists it will remain "ready to deliver" a second runway even if the Government rejects its proposal in favour of Heathrow expansion.