With the final recommendations on airport expansion due next year, Gatwick and Heathrow have intensified lobbying for new runways.
Gatwick's slick campaign has been effective in winning over councils and businesses with the promise of economic growth for the area.
But opposition to proposals is fierce due to fears that a new runway would lead to the urbanisation of Sussex and thousands of new homes.
The massive economic benefits that would be reaped by Sussex make up the well-rehearsed argument for Gatwick's expansion.
The Sussex airport says it offers the quickest, easiest and cheapest option, and would solve the UK's air travel problem for a generation.
The plans would cost between £5 and £9 billion - a fraction of the cost of expansion at Heathrow - and would be privately financed and require a lesser public subsidy.
Meanwhile the impact on noise and air quality would be much smaller than Heathrow, directors say.
Alastair McDermid, Airports Commission Director for Gatwick Airport, is in charge of making its case to the Airports Commission, chaired by Sir Howard Davies, which will make its recommendations to Government in 2015.
He argued Gatwick had the support of businesses and councils and would have a significantly lower environmental impact.
Mr McDermid said: “We do not believe Heathrow will ever be expanded because of the massive environmental impact it would have, which makes it politically toxic as an option.
“Gatwick has support in principle from its closest local councils, is a significantly less complex project from a construction point of view and would have far less noise impact that a new runway at Heathrow.”
He said the airport will work hard to mitigate any environmental impact and compensate those affected by construction.
But he balked at suggestions it would require a town of some 40,000 new homes.
He added: “Predictions of 40,000 are completely out of proportion compared to any previous experience of airport expansion and is scaremongering.
“Clearly there will be some - much smaller - need for additional housing in the area but this need won't arise for another 10-12 years and will be spread over the following 20-30 years.
“There is no prospect of a second runway at Gatwick giving rise to a new settlement as has been suggested by anti-airport campaigners.”
Business is one of the biggest cheerleaders of expansion.
Gatwick Diamond Business, which represents 350 businesses in the area, says it has around 90 per cent support for the proposals among its members.
Jeremy Taylor, chief executive, said: “Gatwick is the best solution because it's cheaper, quicker and the least disruptive - if managed in a way that benefits not just the airport and airlines but also communities around Sussex.
“Infrastructure improvements are achievable. The M23, A23 and Brighton Mainline are already being developed.
“Growing Gatwick will trigger better transport investment and employment - particularly in parts of the county that experience unemployment of 20 per cent.”
Mr Taylor said political expediency had hampered the capacity debate for years. He said: “What we need now is strength from politicians to move this forward.
“Whoever is in power, the MPs of the three main areas will probably oppose it, but it's what's best for the national interest.
“The main economic benefits will be direct employment and figures released last year show we can expect 19,000 new jobs.
“The fear is if we don't have a runway the infrastructure investment will be spent elsewhere.”
But he accepted questions remained over homes.
He added: “Where people are going to live is a key question that remains unanswered.
“But when we hear figures of 40,000 new homes, that is wrong, disingenuous and provocative.
Urbanisation of Sussex
Campaigners say thousands will be affected by noise if the airport gets the all clear for a new runway.
Brendon Sewill, chairman of the Gatwick Area Conservation Campaign, said: “Some people may benefit from the changes but thousands are going to find themselves under a new flight path, with their peace shattered and their house devalued.
The conservation group is arguing that expanding Gatwick would be bad news for everyone within a 20-mile radius of the airport, and would affect around 18,000 homes.
The group points to a study commissioned by West Sussex County Council and Gatwick Diamond Initiative which suggested 40,000 familes would come to the area to work at the airport - a figure proponents dispute.
Mr Sewill added: “We have repeatedly warned that a new runway is not just a strip of concrete but would mean twice as many aircraft in the sky, twice the pollution, twice the climate change damage, twice the noise, and new flight paths over peaceful areas.
“But the issue which is emerging is that making Gatwick larger than Heathrow would lead to the urbanisation of much of Sussex.”
West Sussex County Council has been lured by economic benefits and made a “rushed, undemocratic” decision to support expansion, Mr Sewill said.
Mr Sewill, a Gatwick expert, former civil servant, and opposition campaigner, added: “A new runway would mean more people coming to live in Sussex, more new companies, existing firms expanding, higher total income, and higher council tax receipts.
“But for most ordinary people living in the area at present there would be no economic benefit, just longer queues at road junctions, longer queues at the doctors and at the hospitals, larger classes for their children, more noise, and fewer green fields.
“A vote for a new runway is a vote for a worse quality of life for local residents.”
'The roads cannot support more traffic'
Strong sentiments against expanding Gatwick are agreed by a councillor and long-term resident of Langley Green - which is less than a mile from the airport.
Councillor Brenda Smith, the leader of the Labour group at West Sussex County Council, said: “My parents moved to Sussex because it was a cleaner, greener area than London. A new runway will kill all that.
“There isn't enough infrastructure. The neighbourhood roads cannot possibly support more traffic.
“It's barmy. A second runway is simply not a viable option.
“I hear all the arguments about economic benefits but we don't have the hospital capacity to support 20,000 extra people, it's crazy.
Coun Smith said the airport is already in “a very confined, densely populated area.”
“It's not limitless space,” she added.
“The owners are looking for a nice fat profit to sell it on.
“It's not a philanthropic drive to help the people of the area, it's for shareholders.
“I don't think people get it. They just see jobs, which is understandable, but where will we house all these people?
“We're struggling to build enough homes as it is.
“If anyone thinks I've got a personal interest in this they're wrong - I will probably be dead and buried before it gets built.
“I want to protect the town that's given me a great life.”
The runway debate hinges on whether it is agreed that the South East needs more capacity.
Sir Howard Davies, leading the aviation commission, believes it does - but not before 2030.
His interim report puts Gatwick and Heathrow as frontrunners for expansion, with the possibility of further capacity being needed after 2040.
The issue is a political hot potato for MPs, who will need to weigh up local and national interests.
Several of Sussex's mostly Conservative MPs have come up against the plan.
Crawley MP Henry Smith - the constituency most affected - has opted to delay making a decision until he has more information.
The final decision has been delayed until after the general election in 2015, with many believing only a strong majority Government will have the mandate to push through such a controversial project.
A legal agreement blocking expansion at Gatwick expires in 2019 but the airport could seek planning permission before then in preparation for an expanded airport by 2025.
Politically, Gatwick is seen as having the least effect environmentally in the event of a new runway- though that won't make it any easier for constituency MPs to support the plans.
Option 1: 'Dependent Segregated Mode'
*Close-spaced runways with a separation of less than 760m *Too close to operate independently with operations on one runway temporarily interrupting operations on the other.
*One runway would be used for aircraft arrivals and one for departures.
*Would support around 67 to 70 flights per hour - an overall capacity of some 60-66 million passengers per year by 2050.
Option 2: 'Independent Segregated Mode'
*Runways positioned 760m or more apart, operated independently.
*Arrivals on one runway would not affect departures on the other.
*Capacity would increase to around 75 flights - 75-82 million passengers per year by 2050.
Option 3: 'Independent Mixed Mode'
*Runways at least 1,035m apart *Each runway would accommodate both arriving and departing aircraft to maximise flexibility and capacity.
*Capacity would amount to between 95 and 100 flights per hour or more - 80-87 million passengers per year by 2050.
*The favoured option but the most destructive