The government-appointed Commission into airport expansion has revealed its shortlist of preferred options. It lists a third runway at Heathrow and a second at Gatwick in Sussex.
The Commission, chaired by former FSA chief Sir Howard Davies stopped short of listing Stansted for possible expansion.
The Commission's preliminary report said only one extra runway would be needed in the south east before 2030 with an additional runway likely to be needed by 2050.
Plans for a hub in the Thames Estuary - dubbed "Boris Island" were not shortlisted because of "too many uncertainties and challenges".
It said it would undertake further study of the Isle of Grain option in the first half of 2014 and "will reach a view later next year on whether that option offers a credible proposal for consideration alongside the other shortlisted options".