Plans for a second runway at Gatwick costing £5-9 billion were put forward by bosses of the West Sussex airport today.
They said a new runway, positioned to the south of the current site, could be open in 2025 and would be less expensive and less noisy than an extra runway at Heathrow.
Gatwick chiefs said an additional runway would bring potential investment benefits to Britain of around £56 billion over the period to 2050, would create up to 19,000 jobs and support wider economic and social regeneration.
Also, a two-runway Gatwick would not breach European and national air quality standards and is backed by key local authorities and business groups.
The Gatwick plans will be submitted to the Government-appointed Airports Commission headed by former Financial Services Authority chief Sir Howard Davies.
The commission is due to make its final report on airport capacity in summer 2015.
Gatwick put forward three main options for how a southern parallel runway would operate. The airport bosses said none of the options presented significant project complexity or risk and all could open to passengers by 2025.
Depending on which option is chosen, the airport's capacity would increase from the current figure of 34.2 million passengers a year to between 67 million and 87 million by the 2040s.
Gatwick said the land required for the construction of a second runway had been formally safeguarded since 2003. It is estimated that the potential number of properties lost for the runway options range between 50 and 100 homes at Gatwick, as against 950 to 2,700 at Heathrow if a third, extra, runway is built there.
Also, the Gatwick executives said road and rail access requirements are significantly less than the needs of Heathrow or for the plans for a brand new airport to the east of London favoured by London Mayor Boris Johnson.
Gatwick chief executive Stewart Wingate said: "London is the best -connected city in the world today because the UK's aviation industry is one of the most competitive and innovative.
"Our proposal to the Airports Commission builds on this foundation and would ensure that the UK has an airports policy which offers the additional capacity that Britain needs, improves the resilience of the airports system and, above all, can be delivered."
He went on: "Our evidence shows clearly that an additional runway at Gatwick would best serve the needs of all passengers, and give certainty to airlines, communities and businesses. It would deliver the connectivity the UK needs with lower environmental impacts, whilst spreading the economic benefits.
"A two-runway Gatwick, as part of a constellation of three major airports surrounding London, will also provide flexibility in an industry where the only constant is change."
Earlier, Mr Wingate told the BBC Radio 4 Today programme: "I think there are a number of airlines in this debate with a number of different positions. Certainly some of the Heathrow airlines, as you would expect, support Heathrow, whereas the airlines here at Gatwick are very supportive of the second runway being built."
Mr Wingate admitted that Cabinet Office Minister Francis Maude, who represents the nearby constituency of Horsham, has "reservations" about the plans.
He added: "We have certainly briefed Francis on the plans that we have. I think it is fair to say that Francis has some reservations about the second runway project at Gatwick but is very supportive of the work that we are doing and will see the detail that we layout today and hopefully that will help to convince Francis that this is the right solution."
The Gatwick Area Conservation Campaign (GACC) said there would be "a tidal wave of public resistance" to the second runway plans.
GACC said the plans would mean a doubling of noise and a doubling of the risk to health locally, to climate change and to airport-related traffic.
GACC chairman Brendon Sewill said: "When people begin to realise what is likely to hit them, there will be a tidal wave of public resistance.
"There is no need for any new runway in south east England. With Stansted less than half full, and with new larger aircraft coming into use, there is sufficient airport capacity to last until 2050."
Keith Taylor, the Green Party MEP for South East England, said: "It's no surprise that the bosses of Gatwick want to build this second runway.
"They are hell-bent on bringing more flights into the UK's airspace and they seem more than happy to gloss over the grave environmental and health implications of airport expansion.