Qantas, the Australian airline, has carried out a test flight for what would be the longest non-stop commercial service, delivering passengers from New York to Sydney.
A Boeing 787-9 Dreamliner touched down after a flight of 19 hours and 16 minutes, which was used to assess the effects of ultra long-haul trips on crew fatigue and jet lag for travellers.
Tests included monitoring pilots' brain waves, melatonin levels, and alertness, and there were exercise classes for passengers in economy and business class.
Only 49 passengers were on board in order to minimise weight and give the plane sufficient range to travel more than 9,500 miles without refuelling.
Two Australian universities were involved in monitoring how the health of the passengers and crew was impacted as they crossed multiple time zones.
Immediately after boarding the flight at 9pm in New York the passengers were told to set their watches to Sydney hours, where it was lunchtime.
Lighting, exercise, caffeine and a spicy meal were then used to keep them awake until what would be nightfall in Sydney.
Then they were served a meal high in carbohydrates, told to avoid screens, and the lights were dimmed to encourage them to sleep through the Australian night hours.
Professor Marie Carroll from the University of Sydney, was among the passengers on Qantas flight QF7879, and said she felt "amazingly good" after landing, and expected "minimal jet lag".
She said: "I expect that the passengers will have a normal day today and a normal night's sleep tonight.
"It's all an experiment to see if airlines can adjust their schedule of food, beverages, exercise and lighting to be in sync with the destination time."
Prof Carroll said she and other passengers did stretching and other group exercises at prescribed intervals.
She added: "We did the Macarena in the economy cabin."
Nick Mole, an Australian passenger, said he got almost eight hours’ sleep and felt good, but would not know for sure about jet lag for a few days.
Captain Sean Golding, who led a team of four pilots, said: "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."
In a programme it calls "Project Sunrise" the airline is operating test flights as it looks towards establishing services on marathon routes from the United States and United Kingdom to Australia.
It is aiming 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 - London to Sydney in November, and New York to Sydney in December.
Alan Joyce, Qantas chief executive, called it "a really historic moment" for aviation.
He said: "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."
He added: "After 19 hours on this flight, I think we've gotten this right. It feels like we've been on a flight a lot shorter than that."
Singapore Airlines currently runs the world’s longest non-stop commercial flight, from Singapore to Newark, and it takes 18-and-a-half hours.
The four pilots on board the Qantas flight rotated flying duties and wore monitoring devices.
But the Australian and International Pilots Association, which represents Qantas pilots, has called for a "scientific long-term study" to assess if pilots will get enough quality rest.