Most MPs believe a third runway at Heathrow is the major infrastructure project that will benefit the UK economy the most, according to a new poll.
More than half (55%) of them ranked expansion of the west London hub as the first priority compared with just 14% who chose a second runway at Gatwick.
And more than three out of four (76%) MPs believe building a third runway at Heathrow is an "important factor in Britain's future ability to stay connected to the world" following the UK's exit from the EU.
The poll of 102 MPs - which is the first since the Brexit vote - was commissioned by Heathrow.
David Cameron was expected to confirm whether expansion projects at Heathrow or Gatwick would be supported shortly after the referendum.
But his resignation following the victory for the Leave campaign means the decision has been left for his successor as Prime Minister, Theresa May.
Heathrow chief executive John Holland-Kaye said: "The Government is committed to delivering a positive Brexit plan and MPs couldn't be clearer - an expanded Heathrow is fundamental to Britain's future as an outward-looking trading nation.
"A third runway at Heathrow will open up 40 new markets for Britain's exporters, spur inbound tourism to every corner of our country and create up to 180,000 new skilled jobs.
"By expanding Heathrow, the Prime Minister will make the right choice for a stronger British economy."
In December, the Department for Transport announced that further investigation into noise, pollution and compensation would be carried out before a decision was made.
Gatwick claims it is the only project that can be delivered.