Australia's Qantas Masters Longest Nonstop New York-Sydney Flight

Qantas flight QF7879 took 19 hours and 16 minutes to fly directly from New York to Sydney in the first of three "ultra long-haul" journeys planned by the airline this year.

The national flag carrier is operating the test flights - which also include one from London to Sydney - as it weighs a rollout of regular services on marathon routes from the United States and Britain to Australia.

Just 49 people traveled on the Boeing 787-9 to minimize the weight on board and give the plane sufficient fuel range to travel more than 16,000 kilometers.

Qantas CEO Alan Joyce called it "a really historic moment" for both the airline and world aviation.

"This is the first of three test flights that's going to come up with recommendations about how we manage pilot fatigue (and) how we actually manage passenger jet lag," he told reporters after arriving in Sydney.

"After 19 hours on this flight, I think we've gotten this right."

Qantas partnered with two Australian universities to monitor how jet lag affected the health of passengers and crew members as they crossed multiple time zones.

After boarding the flight, passengers set their watches to Sydney time and were kept awake until night fell in eastern Australia with lighting, exercise, caffeine and a spicy meal.

Six hours later, they were served a high-carbohydrate meal, told to avoid screens, and the lights were dimmed to encourage them to sleep through the night.

Marie Carroll, a researcher from Sydney University who conducted the experiment, said that she expected the innovative approach would result in "absolutely minimal" jet lag.

"I expect that they will have a normal day today and a normal night's sleep tonight," she said, adding that she felt "amazingly good" considering the flight time.

The Australian and International Pilots Association, which represents Qantas pilots, has raised concerns about whether pilots will get enough quality rest during ultra long-range flights to maintain peak performance.

It has called for a "scientific long-term study" into the impacts on crews.