Heathrow's boss says the airport has yet to "engage" with the government about the possibility of ending night flights at Heathrow.
A ban on flights before 6am was one of the conditions the Airports Commission stipulated must be met for a third runway to be built at Heathrow.
Yet seven months after the publication of the commission's report, Heathrow has yet to give a firm commitment on whether it is prepared to accept that requirement.
Speaking publicly on expansion for the first time since December, when the government announced it was postponing its decision on a new runway until this summer , Heathrow chief executive John Holland-Kaye said it was too early to make any commitment on night flights.
"We've said there are no show stoppers in what the commission has said, and there's an opportunity with a third runway to significantly reduce the amount of night-flying," he said.
"We will work with the government and our airlines before we make an announcement that goes any further than that."
Pressed further on when he might be ready to make such a statement, he replied that he had yet to "engage" with the government on the subject.
'Vast majority support expansion'
Addressing Heathrow's Ready to Deliver conference in Euston on Monday (February 9), Mr Holland-Kaye said he believed there was no obstacle to a third runway.
He claimed the vast majority of MPs were in favour and by coming up with a vastly different plan, Heathrow had performed a U-turn so the Prime Minister, who famously promised before the 2010 election that there would be no third runway, wouldn't have to.
The conference also heard from a number of other supporters of Heathrow expansion, including Labour MP Catherine McKinnell, who said it was the best option for businesses in the north east.
Jags Sanghera, who volunteers for the Southall Community Alliance, said most people he spoke to supported expansion at Heathrow because it would mean many more local jobs.
He said employment was the number one issue for most local residents, ahead of concerns about noise or air pollution, but it was important to ensure people living on the airport's doorstep had fair access to better-paid, "high quality" jobs.
"In my experience the vast majority of residents, businesses and faith leaders in Southall are fully in support of expanding Heathrow," said Mr Sanghera, who now works in community liaison for the developers behind the Southall Gas Works site.
The conference was held on the day transport secretary Patrick McLoughlin told the parliamentary transport committee he hopes a decision on a new runway will be taken by late July.