The federal and NSW governments have been told, by their own top advisers, that without a second Sydney airport the economy of the state and the nation will be stunted.

They have been told - in a report delivered earlier this year - that increased traffic will mean Sydney's noise-sharing agreement won't work any more and aircraft noise will rise to the levels considered unbearable in the 1990s.

And they have been told that roads around the airport will be gridlocked and that there will be increasing flight delays, throughout the Australian aviation system.

That's an economic and productivity disaster, right there.

All those hours sitting in a stationary plane on the tarmac, sitting in stationary Sydney traffic, sitting in other airports around the nation suffering knock-on delays are non-productive hours. All those international flights landing in Melbourne or Brisbane because their airports are open for business and expanding and are full of travellers who won't base their holidays out of Sydney.

If we keep on like this by 2060 we'll have lost $60 billion in spending and 78,000 jobs, the report said, and the biggest losses will be in Sydney and NSW.

The federal Transport Minister, Anthony Albanese, read the report and immediately started work on a scoping study at Wilton, south-west of Campbelltown, one of two possible sites identified by the report.

He couldn't start work on the best and most logical option - Badgery's Creek, where the land for an airport still sits, unused, having been bought by the Hawke government in 1985, because he is still bound by Labor's silly, short-sighted 2003 decision to rule out Badgery's Creek. But at least he started work on something.

Barry O'Farrell didn't just refuse to start any work - his government set about undermining the viable options, and even the unviable one that they claimed they supported.

According to the NSW Premier there was only one option for a second airport, Canberra - 300 kilometres away. (The report categorically ruled Canberra out, on the grounds that it's, you know, not near Sydney).

But despite Canberra being the Premier's preference, the NSW government has also approved a rezoning to allow 2000 houses at South Tralee, under Canberra Airport's curfew-free flight path.

Since no one except for O'Farrell really thought that Canberra would ever become Sydney's second airport, this is more a political embarrassment for the NSW government than an actual policy failure, although it does raise serious questions about Canberra Airport's plans to use its curfew-free status to become a big freight hub.

But the NSW government is also actively encouraging plans for 12,000 houses to be built by four developers at Wilton.

Two weeks ago Wollondilly Council - in response to a call for new housing developments by the NSW government - gave the green light to a formal public consultation on plans for a new ''city'' at Wilton.

It will be jointly constructed by four big developers, and include schools, childcare centres, shops and community centres to service the new housing. The council is also strongly backing the already active ''No Airport for Wilton'' campaign.

Local communities have every right to lobby for what they see to be their local interests, but state and federal governments are supposed to take sometimes difficult decisions in the state and national interest. And it is clearly in the state and national interest for a second airport to be built - somewhere.

But for 27 years they've been squibbing it. Privately both sides of Federal Parliament understand they can't squib it for much longer.

The Wilton scoping study should be finished by early next year and it is then that the government will have to say which of the two viable options it is supporting.

Not unreasonably, Tony Abbott has been reluctant to take a lead on the problem from opposition. But importantly, despite O'Farrell's ridiculous position, the Coalition leader hasn't ruled out support for a second airport. He says he is waiting for the specific proposal from Labor.

Many federal Coalition MPs are all too aware that they will inherit the problem if they win government - and that by then the noise and congestion problems in Sydney are likely to be becoming acute. They are also frustrated with O'Farrell's head-in-the-sand stance.

The shadow treasurer, Joe Hockey, who has previously described the NSW government's position as ''absurd'' said this week that it ''does seem odd the state government would approve additional residential housing around Canberra Airport, when it says that should be the second airport for Sydney''.

''The Premier is entitled to his views but we should really be honest and deal with this issue in the Sydney Basin,'' Hockey said.

Many of his colleagues agree, but aren't brave enough to say so on the record.

But the Qantas chief, Alan Joyce, is. He said last month of O'Farrell's position: ''He is wrong on this and we all know he is wrong on this.''

And the Premier's infrastructure adviser, former premier Nick Greiner, is. He said a second airport was necessary, Badgery's Creek was the logical site and there were plenty of reasons why residents might welcome the development.

''Politicians on both sides are running way behind the community,'' he said.

The real question now is how much pain from not building an airport - how much noise, congestion and delays - politicians can endure before it outweighs the political pain of deciding on a site and starting to build the thing.

So far the answer seems to be, a lot. When we finally reach the political pain threshold, the question will be whether politicians can find a way to backtrack from nearly three decades of stupid promises and build it at the most obvious site - Badgery's Creek - or whether they will choose Wilton because it's politically less difficult.

So far we have been waiting more than 27 years. And for all that time politicians have been telling us productivity and economic growth are their abiding concerns.