The boss of Gatwick has said he expects ministers will re-examine forecasts for passenger growth which were "nearly 10 years out" as they conduct further investigation into proposals to expand aviation capacity.
The airport's chief executive, Stewart Wingate, urged them to "peel beyond the executive summary" of the Davies Commission report, which recommend the building of a third runway at Heathrow in July last year.
He told the Press Association: "It's absolutely fascinating because when you look at the conclusions that were drawn it doesn't seem to be consistent with the information that was within the report."
Mr Wingate claims economic impact analysis, which favoured expansion at Heathrow over Gatwick, was based on "spurious, biased forecasts" which did not appear elsewhere in the study.
In December ministers postponed a final decision on which project to back and a final decision is not expected before the summer as Transport Secretary Patrick McLoughlin said fresh analysis of the environmental effects was required.
Mr Wingate said the impact on air quality of a third runway at Heathrow means that project would be "very open to legal challenge" if it is selected, but he also expressed his hope that estimated passenger figures would be looked at again.
"We're expecting they'll want to do work looking at the traffic forecasts," he said.
"The Davies Commission work was based on a set of traffic forecasts that saw Gatwick get to 40 million passengers in 2024. We repeatedly said to the Commission 'We're there already, your forecasts are nearly 10 years out'.
"I'm pretty sure the Government is going to want to take a look at that."
Gatwick recorded 40 million passengers in a 12-month period for the first time in October last year.
Mr Wingate accused Heathrow of attempting to "paint a picture" that it could provide "significantly more" long-haul connections than Gatwick.
An expansion forecast published by the Davies Commission suggested that by 2050 Heathrow would serve 133 long-haul routes compared with 131 at Gatwick.
"It really doesn't matter if you expand Heathrow or Gatwick, the UK will massively benefit from a connections point of view," Mr Wingate said.
"You get the same connections but the price of ours is £7.8 billion versus £18.5 billion at Heathrow.
"What on Earth as a country would lead you to invest unnecessarily £11 billion more on infrastructure which passengers have to pay for?"
The Commission said in November 2014 that a second runway at Gatwick will cost £9.3 billion, but the airport insists this figure includes a contingency fund for unexpected costs which is already part of its own £7.8 billion estimate.
Mr Wingate expressed his hope that the Government will examine the work done by the Davies Commission and then carry out "a more thorough job and a fair job".
He added: "If they do that ... then the Government will be in a position to say 'Actually the right solution for the UK is Gatwick'."
Heathrow chief executive John Holland-Kaye claimed in a speech last week that backing expansion at his airport is the only way ministers can deliver sustainable economic growth and cut the deficit.
He also hit out at Gatwick's plan, saying it did nothing for the economy or job creation and lacked political support.
Sir Howard Davies has previously insisted that his commission "carefully considered" Gatwick's arguments before recommending Heathrow.