Qantas has named Airbus as its preferred supplier for Project Sunrise flights but won’t place an order until a final decision is made on the ultra long-range services in March next year.

Qantas Group CEO Alan Joyce had planned to rule on the business case by the end of this year but ongoing negotiations with pilots have convinced him to push back the final decision.

The choice of the Airbus A350-1000 over the Boeing 777X followed an offer by the European manufacturer to extend the deadline to confirm delivery slots from February to March.

Mr Joyce said the A350 was a “fantastic aircraft” and all going to plan, Qantas would order 12 of the aeroplanes.

“The deal on the table with Airbus gives us the best possible combination of commercial terms, fuel efficiency, operating cost and commercial experience,” Mr Joyce said.

“The aircraft and (Rolls-Royce Trent XWB) engine combination is next generation technology but it’s thoroughly proven after more than two years in service. This is the right choice for the Sunrise missions and it also has the right economics to do other long-haul routes if we want to.”

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He acknowledged that the only hurdle Qantas has yet to clear before launching non-stop flights from Australia’s east coast to cities like New York and London was “efficiency gains associated with our pilots".

“We’re offering promotions and an increase in pay but we’re asking for some flexibility in return which will help lower our operating costs,” said Mr Joyce.

“Airbus has given us an extra month to lock in an aircraft order without impacting our planned start date which means we can spend more time on hopefully reaching a deal with our pilots.”

The offer to pilots includes 3 per cent annual pay increases and multi-aircraft operations – so far as those who fly the A350s would also be able to be used to operate A330s.

Mr Joyce thanked Airbus and Boeing for the “tremendous effort” they’d put in to Project Sunrise.

“It was a tough choice between two very capable aircraft made even harder by innovation from both manufacturers to improve on what they had already spent years designing.”

A final “test flight” by Qantas will take place on Monday, leaving New York at 9pm local time and arriving in Sydney around 10.10am on Wednesday, December 18.

The test flights have all been flown by brand new Boeing 787-9s which are only able to make the distance with a minimal payload of 50 passengers on board. The first flight from New York to Sydney in October took 19 hours and 16 minutes and the second flight from London to Sydney took 19 hours and 19 minutes.

Unlike the other two test flights, Mr Joyce will not be on board, quipping he needed to spend time with his new husband so he wouldn’t divorce him.

Only the second non-stop NewYork-Sydney flight in history, this trip will be conducted as a “control” flight so researchers can compare the health and fatigue effects on pilots, cabin crew and passengers with those on previous services.

If the business case does stack up and the Qantas board gives Project Sunrise the green light, the services are expected to begin in 2023.

Mr Joyce has previously said he would expect passengers to pay a premium for the non-stop flights similar to fares paid for Perth-London services, which have been a runaway success for Qantas.