Work and pensions secretary Stephen Crabb has promised an immediate green light for Heathrow expansion if he is selected as the new Conservative leader.
Crabb has committed to expanding the South West London airport “as soon as possible” after his selection.
A decision on Heathrow was expected this summer, but was again delayed last week by Transport secretary Patrick McLoughlin.
However, Crabb said that further delays cannot be afforded in the aftermath of the Brexit vote.
“Expanding Britain’s airport capacity is vital for our economy and will be even more vital for the new trade links we will need to establish with the rest of the world,” he said.
"At this uncertain time, we need a government prepared to take the strategic decisions needed to put long-term confidence and stability into our economy.”
Crabb's leadership rival Liam Fox has also lent his support to Heathrow expansion.
In a speech today, Fox described the delays to the government's verdict as “scandalous” and promised rapid decisions.
“I personally favour development of a third runway at Heathrow which I know will not be universally popular.
“We must have the courage to see the bigger picture, and implement the decision as soon as possible,” he said.
However, the former defence secretary raised questions over HS2.
“There is no doubt that we need better connectivity, reliability and capacity but I’m not convinced that we need to be spending an inordinate amount of money and time getting the straightest track so that we can have the fastest trains possible,” he said.