The government commission examining airport capacity in the south east has started a fresh consultation on plans for a four-runway hub airport in Kent.
The Davies Commission says it wants to hear views about the idea of an airport on the Isle of Grain before deciding whether it should be included in a final shortlist.
The commission says it will decide by September if the scheme, backed by Mayor of London Boris Johnson, is feasible.
An aerial image of Lord Foster's proposed Thames Hub airport at Grain
Last month, the commission headed by Sir Howard Davies said it could not reach a firm conclusion and wanted time to consider a hub airport on the Isle of Grain in more detail.
It is being promoted by the company of world-renowned architect Lord Foster.
A 12-page report announcing the fresh consultation and call for evidence says the Thames Estuary schemes submitted during the first stage of the review “were both imaginitive and ambitious”.
It said the idea “of a once-in-a-lifetime decision to build a new hub airport that would significantly reduce the impacts of flying into and out of London...is compelling.”
But it also acknowledges the potential adverse impact on the area, notably the environment.
Lord Foster's plans for a four-runway airport at Grain have provoked a strong reaction
It said these, along with operational issues and the economic and social impacts, would determine whether it was feasible.
The commission will publish an analysis and evidence it receives in June, which will then be subject to further consultation.
A final decision will be made in September on whether the scheme is credible and join expansion options for Gatwick and Heathrow.
The commission will then publish its final recommendations in 2015, after the general election.
The deadline is May 23.