US approval of the proposed joint venture between American Airlines and Qantas Airways could slip a few months to early 2019, says Qantas chief executive Alan Joyce.

The Oneworld Alliance carriers are "very optimistic" that the tie-up will get a nod from antitrust regulators but, with the Christmas and New Year holidays imminent, approval may not come until early in the new year, he tells FlightGlobal on the sidelines of an alliance event in New York today.

American and Qantas reapplied for immunity with the US Department of Transportation in February, just over a year after a previous joint venture application was rejected by the regulator in 2016.

The airlines have emphasised the economic benefit of their partnership, which tally at $310 million annually. In addition, they have promised to add at least three new routes between Australia and the USA if approved.

"We're very positive," says Joyce on the likelihood of approval.

An immunised joint venture allows airlines to essentially act as one in a market. For example, they can coordinate schedules and fares, jointly market and sell flights, and pool revenues under the agreements.

American executive vice-president of corporate affairs Stephen Johnson had a similarly optimistic outlook in July, when he said US regulators were taking a new approach to analysing the benefits of joint ventures with the American-Qantas proposal.

"They're taking really a fresh and, I think, very thoughtful look at the whole concept of antitrust immunity around JVs, and Qantas is turning out to be the platform for that," he said. "It has taken a little longer than we'd hope. But we remain optimistic that it's going to get done."

The carriers expected approval by year-end, he said at the time.

An American-Qantas tie up would put the codeshare partners on equal footing with the joint ventures between Delta Air Lines and Virgin Australia, and United Airlines and Air New Zealand.

Source: Cirium Dashboard