Prime Minister Theresa May signalled a decision "will be made shortly" at the Conservative Party conference on Wednesday (October 5).
The Government decision would mean choosing between a third runway at the country's busiest airport or a second runway at Gatwick Airport, ending what is one of west London's longest standing issues.
Although the Airports Commission said a third runway at Heathrow would be the most economically beneficial option, ministers postponed the decision to examine environmental concerns raised by campaign groups.
Rumours of expanding both airports have already been quashed by Transport Secretary Chris Grayling who ruled it out at the Conservative party conference.
A group of residents against the runway visited the conference at the ICC in Birmingham carrying a papier mâché aeroplane bearing the message “No 3 Runway" to show the delegates.
Harmondsworth resident Neil Keveren said: "We’re here in Birmingham to remind the party of the Prime Minister that a third runway is not a good deal for Britain.
"Residents are united against expansion and will not be forced out of their homes by the Government."
Speculation as to whether there will be a free vote in Parliament continues, although it would allow prominent anti-Heathrow third runway MPs such as Boris Johnson and Zac Goldsmith to impact the decision.
Five local authorities, including Hillingdon, Richmond and Hammersmith and Fulham have already written to the Prime Minister to say they will prepare for a legal battle should the decision for Heathrow expansion go ahead.