South east of England will need new runways if it is to meet air travel demand, says Davies

Sir Howard Davies, chair of the Airports Commission, was speaking as the group set out its "emerging thinking" on how to maintain the UK's status as an international air travel hub. The Commission is inviting comments on its analysis, which will inform the publication of its interim recommendations before the end of the year.

"Our provisional conclusion is that we will need some net additional runway capacity in the south east of England in the coming decades," said Davies, in his first major public speech. "To rely only on runways currently in operation would be likely to produce a distinctly sub-optimal solution for passengers, connectivity and the economy and would also almost certainly not be the best solution in terms of minimising the overall carbon impact of flights and travel to and from airports."

The UK would also need to develop a "mechanism for managing the carbon impacts of aviation" in order to comply with its statutory climate change targets, he said. It would need to do so even without new runways and the accompanying increase in emissions from aeroplanes, he said.

The Airports Commission is due to present its interim report by the end of this year, with a final report due by summer 2015. The Commission, chaired by former Financial Services Authority head Davies, will report on the need for additional capacity and how quickly, and will set out how that need should be met in the short, medium and long term.

The UK's existing hub, Heathrow Airport, is currently operating at almost full capacity. The Government cancelled plans for a proposed third runway at Heathrow when it took office in 2009 but has acknowledged the need for an alternative, which could include a new airport in the Thames Estuary or additional runways at Heathrow, Gatwick or Stansted. Passenger demand for London's airports is forecast to increase from 140 million a year in 2012 to 400 million passengers a year by 2050, according to the Greater London Authority.

In his speech, Davies said that the Commission had received over 50 responses to its call for proposals, and planned to publish a "short-list of options for new or expanded capacity". In its own submission, Heathrow has made the case for a third runway, while Gatwick Airport has proposed a "constellation" of three London airports with two runways each as a more competitive approach which is also more resilient to disruption. The Mayor of London's office has proposed the construction of a new hub airport in Kent, at Stansted or in the Thames Estuary.

The Commission had also received a number of submissions arguing against the need for any additional capacity, he said. Some of these were based on the environmental impact of increased air travel, while others suggested making better use of available capacity at regional airports. However, Davies said that it was "difficult to see" how these airports could absorb all the excess demand, and pointed out that the Government had little power to influence the location of flights.

"It may also not be the best solution in terms of minimising the overall carbon impact of flights and travel to and from airports," Davies said. "More point to point flights in smaller aircraft, together with long passenger movements to airports remote from them, bring significant disadvantages. A mechanism for managing the carbon impacts of aviation will be needed if the UK is to achieve its statutory carbon targets – just as it will in other countries. But this is the case whether new runway capacity is provided in the south east or not."

The Commission would consider whether it was possible to deliver some "modest additional capacity" in the short term through operational improvements as part of its interim report. It would also look at potential measures to improve transport links to south east and some regional airports, Davies said.