Gatwick bosses are beginning detailed work on the option for a new runway at the airport. But the plans will honour a 1979 legal agreement that no runway can be built before 2019.
The options will be submitted to the Government-appointed aviation commission led by former Financial Services Authority (FSA) chief Sir Howard Davies boss which will make its full report in summer 2015.
Gatwick chief executive Stewart Wingate said a new runway at Gatwick "could be affordable and practical" and was a better option than new runways at Heathrow or Stansted airports.
The work on a new runway at Gatwick, which serves 197 destinations and handles around 34 million passengers a year, will evaluate various runway options and assess key requirements, including environmental, surface access and economic impacts.
Relevant environmental issues will include noise and air quality impacts on local communities.
Gatwick chiefs believe that the additional capacity, flexibility and resilience that could be provided by a new runway at Gatwick will help to ensure that London's airports provide south-east England and the UK with the connectivity needed.
The bosses said that at least for the rest of this decade, London's airports will be relying on their existing physical capacity.
Gatwick's work, and subsequent submission to the Davies Commission, will include a detailed evaluation of how Gatwick's existing single runway capacity can be maximised to contribute to the short-term capacity needs for London and the UK.
Mr Wingate said: "Over the last three years we have transformed the airport, invested around £650 million and have a strong track record for delivering key routes to growth markets.
"However, we must now look to the future when Gatwick will become full and outline its long-term role in ensuring London has an efficient and resilient airport system that creates the crucial connectivity London and the UK needs."
He went on: "I believe a new runway at Gatwick could be affordable, practical and give passengers a greater choice of routes to key markets. A new runway will allow Gatwick to compete and grow, increasing the choice available to passengers today. We have the space, capability and access to financial resources.
"There are clear practical advantages of a new runway at Gatwick. When compared with a third runway at Heathrow, we would have a significantly lower environmental impact whilst adding significantly more capacity.
"Stansted is half empty today, we already have much better surface transport links and feel our business case will be much stronger."
Mr Wingate continued: "As for the (Thames) Estuary airport concepts (favoured by London Mayor Boris Johnson) there are major questions on affordability, environmental issues and whether they are deliverable.
"The process of evaluating the runway options will be complex. I am committed to undertaking a comprehensive and in-depth assessment that considers not only the economic benefits but also the environmental impacts. We will be consulting with our key stakeholders throughout the process."