Gatwick Airport is looking at options to build a second runway, according to reports.
News agency Reuters said the airport intends to submit findings from the report to the government, despite a local agreement that a second runway could not be built at Gatwick until 2019.
Stewart Wingate, Gatwick chief executive, said: "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.
"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."
Gatwick, which is owned by Global Infrastructure Partners, serves about 34 million passengers each year.
The government is coming under pressure to resolve a capacity crisis in the south-east, with Heathrow operating at full capacity.
An independent commission chaired by Howard Davies is due to report in 2015.