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An Airbus A350 holds the World record for the longest non-stop flight
Charles Raisor from Quora asks the above question. I assume he meant ‘running out of fuel’ rather than ‘running out of gas’. Only piston propeller planes use gas or avgas (aviation gas). Modern commercial airliners run on jet fuel of various grades.
Yes, planes never fly until they run out of fuel! You can only do that on a car because it merely stops on the road. On a plane, it may crash just like one conspiracy theory where it was alleged that MH 370 ditched after it ran out of fuel.
Currently, what has been documented are records of some of the world’s airliners that have achieved the longest distance with certain flight times. Generally, flight records are not stated in terms of how long it flew over a particular distance because flight time depends on the wind.
Longest non-stop flights
On 8th February 2021, Singapore Airlines set the World record by flying an Airbus A350 from JF Kennedy Airport in New York to Singapore non-stop in 18 hours and 40 minutes over 15,374 kilometers.
Theoretically, it could fly longer because all commercial planes land with a regulated diversion and reserve fuel and never with zero fuel. As such, the answer is that it could stay more than 20 hours in the air before running out of fuel.
Recently, the Covid-19 induced turmoil has made planes to fly even longer non-stop flights.
On 29th March 2021 Austrian Airlines flew 16,000 km to Sydney from Vienna to pick up Austrian citizens stranded in the city.
On 14th April 2021, Virgin Atlantic flew even further from Paris to Brisbane at a distance of 16,500 km to repatriate French citizens home.
Conclusion
So how long can a plane fly without running out of fuel?
Aside from record breaking passenger-carrying flights, there are other aircraft that can stay much longer in the air.
In-flight refueling can of course extend a flight’s duration in the air. For instance, the Presidential US Air Force One with inflight-refueling facilities can stretch its time in the air for days. Some say, it can stay in the air for about 3 days. Any longer is restricted by engine oil limitation. Others were of the opinion that water on board may limit its time in the air.
However, the plane piloted by Dick Rutan and Jeana Yeager named Rutan Voyager still holds the record for the longest non-stop, non-refuel airplane flight in history. It stayed for 9 days and 3 minutes in the air.