Boris Johnson has refloated the idea of an island airport as an alternative to a third runway at Heathrow.
Plans to create a hub airport in the Thames Estuary were rejected by the Airports Commission (AC) in 2014.
In a report entitled Landing The Right Airport, the mayor says a four-runway airport east of London is the only way to secure enough capacity.
Opponents previously described "Boris Island" as "financially, geographically and environmentally wrong".
'Only credible solution'
"If we are to secure the connectivity we need to support our future growth and prosperity and do so without dire impacts on public health - then we must do better than Heathrow," Mr Johnson said.
Building an airport at one of two locations in the Thames Estuary or expanding Stansted in Essex "away from populated areas" was the "only credible solution", according to the Mayor of London.
In his forward to the 78-page document, he added: "Each could accommodate the four-runway hub that London and the UK needs.
"Our analysis predicts that they would offer around double the number of long haul and domestic destinations served by Heathrow today, while exposing 95% fewer people to significant aircraft noise.
"A four-runway hub to the east of London, rather than jarring with the growth of London will support it, catalysing regeneration and housing to the east."
In July, the AC recommended building a new runway at Heathrow rather than providing a second runway at Gatwick.
But it did not completely rule out another runway at Gatwick or doubling an existing runway at Heathrow.
The government has delayed its decision on airport expansion in the South East until the summer at the earliest, saying more work needed to be done on the potential environmental impact.
In September 2014, Sir Howard Davies, chairman of the commission, said the cost, economic disruption and environmental issues made the Thames Estuary airport plan unviable.
Daniel Moylan, aviation adviser to Mr Johnson, said a hub airport to the east of London would cost £20bn to £25bn - with an extra £25bn required to building road and rail connections.
Constructing a third runway at Heathrow is estimated to cost £18.6bn, but Mr Moylan said that did not take into account the amount of money needed on surface access and measures to stop congestion, which the new report claims could be as high as £20bn.