Brisbane International Airport has launched a key stage in its controversial new runway project, even though it has still not reached a funding deal with its largest operator, Qantas Airways.

The airport has been attempting to gain support from its tenant airlines for its A$1.35 billion ($1.3 billion) second parallel runway, since the carriers will be helping pay for it through ticket taxes. An airport spokeswoman says of all the airlines using Brisbane only Qantas is not onboard.

While the airport has previously indicated that it wanted to have airline agreements in place before it would begin earthworks, it has decided it must start to meet its goal of opening the runway by 2020. ”We’re not going to wait around forever, now’s the time to move ahead,” the spokeswoman says.

This decision was partly based on the fact that the airport’s board is “very confident” that it can reach a funding agreement with Qantas, the airport spokeswoman says.

However, it appears that this view could be overly optimistic, as Qantas is still opposed to the way Brisbane airport wants to fund the runway. The carrier says it is not opposed to the runway project itself, but disagrees with the airport’s proposal to have airlines start paying more before the runway is in use.

“We are pleased that Brisbane Airport is getting on with the next stage of the runway project, which is vitally important for [the state of] Queensland,” says Qantas Domestic CEO Lyell Strambi. “[But] it is standard practice around Australia and the world for airport owners to invest in new infrastructure and for airlines to pay once the infrastructure is in use.”

The International Air Transport Association (IATA) has also weighed in on the Brisbane runway issue. In July, IATA CEO and Director General Tony Tyler said that pre-financing efforts such as this contravene the principles of infrastructure development that have been agreed through the International Civil Aviation Organization.

Some preliminary work on the runway site has already begun. The airport has now awarded a contract for the next phase, which involves dredging and land reclamation. About 13 million cubic meters of sand will be dredged to help stabilize the soft ground. The final phase of the project, the laying of pavement, is expected to begin in 2016 or 2017.

The Brisbane Airport Corporation stresses that it will contribute 75% of the cost of the new runway through debt and equity investment. The remainder would be paid by airlines through ticket taxes. Virgin Australia has already reached a new deal with the airport that includes funding for the new runway.

Brisbane Airport is the third-largest in Australia, and the second runway is considered vital to reducing air traffic congestion.