Qantas Airways completed a non-stop test flight from London to Sydney on Friday, as part of a trial to determine whether to launch the world's longest ever commercial route.  

Qantas will use feedback from this test, which took 19-hours and 19-minutes, to help decide whether to order a fleet of Boeing 787 Dreamliners, which would be used on this route. If it does, the first commercial flight would not be scheduled until 2023. 

The test flight carried just 40 passengers and crew, and had enough fuel for another hour and 45 minutes of flight time.

Analysts forecast non-stop flights from Sydney to London and Sydney to New York could add $120 million to the company's annual profits. Qantas would charge a premium for cutting out a stopover, but no official prices have been released.

The current average cost of a Qantas flight from London to Sydney is $928.

Research was conducted on the flight to assess how people on board behaved and coped with an ultra-long-haul journey. 

Corinne Caillaud, an assistant professor at the University of Sydney, said: "What we've done, basically, is to design three very important things on the flight. First, the lighting, then the meal schedule and the meal composition, and physical activity onboard. 

"And why we are doing it on this very long flight? To help people to adjust better when they arrive in Sydney and to reduce jet-lag on arrival."

The journey is being referred to as "Project Sunrise." Alan Joyce, CEO of Qantas, said he saw a "double sunrise" on the flight, and the design of the aircraft would help to combat the fatigue of long journeys. 

Joyce said: "Our intention is to have bigger seats in economy than we've ever had before, have dedicated stretching areas. It is a very designed product for long-haul travel."

Andy Chevis, a research passenger on the flight, said: "I actually feel fantastic, I feel really well. Probably a lot better than I normally would at this point in the flight, to be honest."

The majority of people on board were Qantas employees, fitted with monitors to track their sleep patterns, food and drink intake and physical movement. 

This aircraft is not the first to fly the route non-stop, with the same journey first being completed in August 1989. That aircraft, which only transported crew, is now in a museum.

In 2018, Qantas completed a direct flight from Perth in Australia to London, which is a 17-hour flight. 

Qantas also flew a Dreamliner non-stop from New York to Sydney in October, but the journey is about 1,600 kilometers shorter.