American Airlines and Qantas have re-filed an application with US regulators for an immunised joint venture, in the hope that the Trump administration will be more welcoming of the proposed deal.

The two Oneworld carriers say in a filing with the US Department of Transportation (DOT) that the partnership could stimulate up to 180,000 new passengers on routes between the USA and Australasia.

The two airlines add that the joint venture could also result in $310 million of "quality of service benefits" such as improved connections as well as lower fares.

American and Qantas withdrew their application with US regulators for an immunised joint venture after the DOT tentatively proposed to block it in November 2016, following competition concerns raised by Hawaiian Airlines.

After the Trump administration came into power, Fort Worth-based American said it would re-apply for antitrust immunity with its Australian partner. Regulators in Australia and New Zealand had earlier approved the tie-up.

Honolulu-based Hawaiian did not immediately respond to questions on American and Qantas' re-application.

American says it "will have no choice" but to further reduce codesharing with Qantas if the joint venture is not approved. The two airlines say they had cut back on co-operation since the tentative rejection of their previous application for antitrust immunity.

"American has been forced to downgrade its service to Australia and New Zealand, and the parties have stopped codesharing on flights between the United States and Sydney," say the airlines in its DOT filing.

The two carriers codeshared on about a hundred flights a week in November 2016, when their application for antitrust immunity was tentatively rejected by the DOT, FlightGlobal schedules data show. This has reduced to about 70 flights weekly this month, the data show.

Among the dropped codeshares are on Qantas' flights to Los Angeles and Dallas/Fort Worth from Sydney, and on American's flights between Los Angeles and Sydney.

American says Qantas may be forced to reduce or cancel its Airbus A380 service between Sydney and Dallas/Fort Worth, while American may reduce flights from Los Angeles to both Sydney and Auckland, if approval is not granted by US regulators."These routes rely on codeshare support from each airline’s feeder network via their respective hub cities to be economically viable," says American.

FlightGlobal schedules data show that the vast majority of passengers travelling on Qantas' flight from Sydney to Dallas/Forth Worth for the year ending December 2017 were connecting passengers. About 13% of passengers on the route flew only the segment nonstop.

Source: Cirium Dashboard