Thursday's flight will top the current longest direct air link between cities -- Qatar Airways Flight 921 from Auckland to Doha, which takes 17 hours 40 minutes
The world's longest commercial flight took off from Singapore on Thursday, with excited and apprehensive passengers on board settling in for a marathon 19 hours in the air to New York.
A spokeswoman for Singapore Airlines told AFP that Flight SQ22 departed at approximately 11:35pm (1535 GMT) with 150 passengers and 17 crew on board.
Two pilots, a special "wellness" menu and more than seven weeks' worth of film and television entertainment accompany the travellers on the 16,700km journey to the Big Apple.
The long-range Airbus A350-900ULR is configured to carry up to 161 passengers -- 67 in business class and 94 in premium economy, with no regular economy seats available.
For the flight crew -- which also includes two first officers and a 13-strong cabin contingent -- the workload will be broken up, the airline said, with each pilot having a minimum eight hours' rest during the flight.
But for passengers, the challenge will be what to do with all that down time when they're up in the air.
For those not packing a weighty novel (or two), there will be 1,200 hours of audio-visual entertainment to choose from.
Dining options will include dishes the airline says have been selected to promote well-being in the skies, with organic offerings on the menu.
Passenger Peggy Ang, 52, said before the flight that she felt "apprehensive because I'm not sure what would I do in 18.5 hours" inside the plane.
"Now that you asked me, I'm a little bit worried. I'm thinking of sleeping, watching TV, doing my work," she told reporters after checking in at Changi Airport for the flight.
"I have a lot of notes to read, hopefully I can sleep well," said Ang, a membership director of an IT services firm.
Some of the passengers were flight enthusiasts, like Singaporean engineer Danny Ong, 50, who bought a return ticket.
"I'm coming back on the next flight. I enjoy the passion of flying," he told AFP, adding he would binge on the in-flight entertainment.
Pier Messaggio, 41, an Italian electronics designer based in Singapore, said he is part of a group called "First to Fly" whose members have been on board all of Singapore Airlines' inaugural flights.
He and his group met during the world's first commercial flight of the Airbus A380 double-decker plane operated by the airline in 2007 and discovered that everyone had a passion for flying.
"I fly for fun... I'm an aviation enthusiast," Messaggio told AFP.
Airbus said the A350-900URL plane's cabin has higher-than-normal ceilings, larger windows and lighting designed to reduce jet lag -- all part of an effort to lessen the stresses that can accompany almost a day on a plane.
"Research has shown that hydration and food intake are important factors (to consider), such as avoiding foods that cause gas or bloating as well as excessive alcohol," Rhenu Bhuller, a healthcare expert at consultancy Frost & Sullivan, told AFP.
"The biggest concern is Deep Vein Thrombosis from a combination of sitting for too long and also from dehydration," said Gail Cross, an associate consultant at the National University Hospital in Singapore.
The twin-engine plane uses a modified system that burns 25% less fuel than other aircraft of a similar size, Airbus said.
The flight from the city-state to Newark Airport can take up to 18 hours and 45 minutes under normal weather conditions, but the pilots will have something in reserve in an aircraft capable of flying more than 20 hours non-stop.
Singapore Airlines originally flew the route for nine years using the gas-guzzling, four-engine A340-500 before abandoning it in 2013 because high oil prices made the service unprofitable.
But the carrier is hoping that the introduction of more fuel-efficient planes will set cash registers ringing even as crude prices soar above $80.
Thursday's flight will top the current longest direct air link between cities -- Qatar Airways Flight 921 from Auckland to Doha, which takes 17 hours 40 minutes.
"It's turning out to be a race between a few airlines eyeing the longest routes inter-continentally," said Shukor Yusof of aviation consultancy Endau Analytics.
"They are hoping to capitalize and exploit a very niche market," he told AFP.
Facing increasingly strong competition in recent years, Singapore Airlines has consolidated its low-fare subsidiaries and is strengthening its premium segment.
"Ultra-long haul services comprise an important component of that strategy," an airline spokesman told AFP.
The company is the first airline in the world to operate the A350-900ULR plane. It received the first aircraft in September. Six more are due for delivery by the end of the year.
"We are optimistic about the demand for non-stop services to the US," the spokesman said.
Analyst Shukor, however, said it remained to be seen whether the airline and other operators of marathon flights can withstand the pressure from rising oil prices.