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.
Twitter users have posted pictures from Edinburgh Airport that appear to show the disturbance caused by its closure this afternoon, following the discovery of a "potentially suspicious" bag.
Bomb disposal experts have arrived at the airport to investigate the package.
A Police Scotland spokesman has told STV: "Police at Edinburgh Airport have implemented a closure of the building and the access roads following the discovery of a potentially suspicious bag within the Central Search Area at around 1.50pm today.
"The EOD are currently in attendance to inspect the item and officers are maintaining a cordon to ensure the safety of the public."
Edinburgh airport has been evacuated over suspicious package, it has been reported.
Edinburgh Airport evacuated after suspect package found in building http://t.co/Jqq0G6rrZy
Edinburgh Airport Evacuation: Passengers moved onto airfield while authorities investigate suspect package. http://t.co/2q2gA8ePoy
London Mayor Boris Johnson has said that a new airport in the Thames Estuary - so-called Boris Island - would cost far less than is claimed in today's Airports Commission report.
According to the report, the scheme could cost between £82 billion and £112 billion and would result in airport charges around three times higher than those projected for Heathrow.
Johnson insisted the total cost would be around £50 billion - £20 billion for transport links and £30 billion for the facility itself, which he predicted could be funded from private investment.
Here is a summary of the main points from the interim report by the Independent Airports Commission:
- Heathrow is effectively full and Gatwick is operating at more than 85% of capacity
- Aviation demand "likely to increase significantly between now and 2050"
- Demand is likely to be concentrated in the South East, where more people live and wages are higher on average
- There is a need for one additional runway to be in operation in South East by 2030 and likely to be demand for a second one by 2050
- Proposals for additional runways at Heathrow and Gatwick were short-listed. 'Boris Island' proposal in Thames Estuary will be looked at in first half of 2014 and may join short list.
Conservative MP Zac Goldsmith said he would not stand as a Conservative party candidate if David Cameron regaled on his "No ifs, no buts" earlier position on building another runway. Speaking to ITV News he said:
"If we go into the next election with a green light for Heathrow expansion, I would not able to stand as a Conservative."
Of the three options for expansion presented by Heathrow Airport Ltd in the summer, the Airports Commission is only progressing one of them: the plans for a new runway to the north west of the existing airport.
The other Heathrow idea being investigated by the Commission comes from a pressure group called Heathrow Hub: the extension of one of the current runways.
The proposal is to build a third runway to the north west of the existing airport. It is a different proposal to the one approved by Gordon Brown when he was Prime Minister.
The new runway is further to the west - and anyone who knows this area will work out it brings the runway of Britain's busiest airport into conflict with Britain's busiest motorway, the M25. Look at the plan and you will see the runway is built over the top of the motorway.
That is not unusual. At Paris' Charles de Gaulle airport, a motorway passes under one of the runways in a tunnel. But it does mean this option is not cheap.