Australian airline Qantas has completed the first non-stop commercial flight from New York to Sydney.
It was used to carry out a series of tests to assess the effects of ultra long-haul flights on crew fatigue and passenger jetlag.
The Boeing 787 Dreamliner touched down in Sydney early on Sunday morning after a flight of 19 hours and 16 minutes - the world’s longest.
Qantas said tests ranged from monitoring pilot brain waves, melatonin levels and alertness, to exercise classes for passengers.
A total of 49 people were on board, in order to minimise weight and give the necessary fuel range.
"Overall, we're really happy with how the flight went and it's great to have some of the data we need to help assess turning this into a regular service," said Captain Sean Golding, who led the four pilots.
The flight was part of Project Sunrise - Qantas's goal to operate regular, non-stop commercial flights from Australia's east coast cities of Brisbane, Sydney and Melbourne to London and New York.
Two more research flights are planned as part of the project evaluations - London to Sydney in November and another from New York to Sydney in December.
"We know ultra long-haul flights pose some extra challenges but that's been true every time technology has allowed us to fly farther. The research we're doing should give us better strategies for improving comfort and well-being along the way," said Qantas Group chief executive Alan Joyce.
Night flights usually start with dinner and then lights off but, for this flight, he said: “We started with lunch and kept the lights on for the first six hours, to match the time of day at our destination. It means you start reducing the jetlag straight away.”
Professor Marie Carroll, from the University of Sydney, said she and fellow passengers did a lot of stretching and group exercises at prescribed intervals.
“We did the Macarena in the economy cabin,” she added.