Qantas, the biggest operator at Perth Airport, has given its blessing to building a new runway to eliminate congestion at WA's gateway to the world, but the precise timing is yet to be determined.
Yesterday, Qantas chief executive domestic Lyell Strambi told The Weekend West the airline had endorsed plans to proceed with a two-year environment study before a final decision on the timing of building the third runway.
Perth Airport has two cross-runways that cannot be used at the same time and then only in certain wind conditions.
The third runway would be parallel to the main north-south runway and allow simultaneous operations, doubling the airport's capacity.
Though most airlines agree the third runway is needed, its timing and cost have been sticking points, with the slowdown in domestic traffic - as the resources boom cools - making it difficult to finalise the $500 million project.
"We agree a third runway is required at the earliest in 2019," Mr Strambi said.
"However, it is important that we have all the approvals in place in case we need to fast-track the project."
Perth Airport chief executive Brad Geatches said yesterday the airport remained "committed to progressing the runway and is pleased with the responses received from airlines so far".
"Generally, airlines have indicated they wish to work with Perth Airport on the planning, consultation and approvals stages of the new runway project," he said.
"The exact timing of construction will be influenced by how demand for aircraft movements develops during the next two years.
"By proceeding with the first stages of the project we will be well-positioned to respond to demand in a timely manner."
Mr Strambi and Mr Geatches agreed a new schedule co-ordination system, improved practices and a slowing in demand had contributed to less congestion and better on-time performance at the airport.
But bottlenecks remain midweek and traditionally slowdowns - which typically happen every 10 years - have lasted only 18 months.
There are also air traffic snarls in wet weather.
Though domestic traffic has stagnated, international traffic through the airport has leapt 12 per cent this year.