Expansion of Heathrow and Gatwick are the shortlisted options being considered by a government-backed commission into airport expansion. In its interim report, the commission also says a new airport will be needed in the South East by 2030.
There are serious cases for third and fourth runways at Heathrow airport, a group of MPs have said ahead of the first stage of publication of a Government-backed report into expansion at the west London airport.
The transport select committee said Heathrow was already operating at full capacity and the case for a fourth runway may "have merit".
The Government-appointed Airports Commission is expected to publish its first report into airport congestion in the UK, chaired by former Financial Services Authority chief Sir Howard Davies.
As well as publishing measures to ease airports congestion in the short term, the commission will reveal a short list of extra runway options - a list expected to include expansion at Heathrow.
However, firm proposals will not be made until the commission publishes its second, and final, report in summer 2015 - after the next general election.
Some believe today's report did not draw firm conclusions in order to avoid a politically divisive issue before the next election.
Expansion of Heathrow and Gatwick Airports are the shortlisted options being considered by a government report into airport expansion.
Heathrow is the third busiest airport in the world in terms of passenger numbers. It carried more than 69 million people in 2011.