Chancellor John Healey has shown support for expanding Heathrow Airport after Prime Minister Andy Burnham refused to back plans for a third runway.
Mr Healey said adding an extra runway at one of the busiest airports in the world could boost growth.
"The case for a third runway at Heathrow has always been a case for growth," he told reporters on Friday at the International Monetary Fund's annual meeting in Bangkok.
Last month the prime minister refused to back the plans for a third runway, telling the BBC the decision was a matter "for London and Londoners".
The previous Labour government led by predecessor Sir Keir Starmer and then-chancellor Rachel Reeves backed the decision for a third runway, but Mr Burnham's comments have led to uncertainty.
Many businesses, airlines and investors have said the airport should expand but some local residents have objected to the noise from more planes.
The UK's climate targets could also be at risk from adding thousands more flights.
Meanwhile, ministers are understood to be lining up advisers to assess the affordability of Heathrow's third runway plan amid growing expectations that it will miss its 2035 completion deadline by four years.
Estimates suggest a third runway at the airport could support 100,000 new jobs, but there are concerns the eventual cost has been underestimated and fears passengers face huge hikes in fares to cover the costs.
Heathrow says the runway itself will cost approximately £33bn, with associated infrastructure improvements taking the overall budget to £49bn.
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Earlier this week the transport secretary insisted "Britain loses by standing still" as she said Heathrow expansion could help grow the economy.
Heidi Alexander told business leaders at the AirportsUK annual conference the government still needed to make a final decision about the expansion plans following a consultation.
"A third runway has the potential to create new opportunities, jobs, investment and growth in every corner of this country," she said.
It came after Heathrow chief executive Thomas Woldbye told BBC Radio 4's Today programme he hoped the prime minister would throw his weight behind the third runway scheme, adding "it would be good to know where government is on this".
The prime minister's official spokesman has previously said economic growth "is obviously very important" and acknowledged the potential boost that could be delivered by a third runway.
But added: "This is a major privately financed infrastructure project, and there's a proper process to go through. It's entirely right that the prime minister considers the detail and listens to the views put forward.
"Any final decisions will have to meet the tests we've set on climate, noise, and air quality. But there's currently no live planning application for a third runway."
(c) Sky News 2026: Heathrow expansion would boost growth, chancellor says


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