Non-stop passenger flights from Australia to Greece and other European destinations could be introduced under European plans to refuel commercial planes mid-air.
Scientists and engineers are working on a system which will allow commercial jets to take on fuel without landing, significantly extending the time they can stay in the air.
The project, funded by the European Union, has already found that overall fuel consumption may be cut by up to a quarter by allowing planes to take off and land with a lighter load.
A collaborative team of scientists from nine institutions across Europe has designed a so-called Cruiser-Feeder concept that would allow planes to refuel in mid-air.
The system would involve a refuelling plane, carrying enough kerosene to top up up to five passenger planes, located at various points along flight routes.
As the passenger plane approaches, the refuelling jet would take off, fly beneath the plane before connecting specially-designed and made fuel tanks and pumps.
It would then off-load the required amount of kerosene before disconnecting and returning to the ground.
An alternative scenario would see the jet circling in the air until it is needed.
Refuelling would only be carried out near the main airways and away from inhabited areas.
The civil concept was developed as part of a wider project called Research for a Cruiser Enabled Air Transport Environment (Recreate).
It is a technique already used by the military, for example, to refuel state aircraft.
The researchers, led by the National Aerospace Laboratory (NLR) in Amsterdam and the Zurich University of Applied Sciences (ZHAW), said kerosene reserves make up about a third of the weight on long-distance passenger flights at take-off.
Reducing them and refuelling mid-air could mean ‘huge savings’ and figures suggest fuel burn, and therefore the amount needed at take-off, could be reduced by up to 23 per cent for every 6,000 nautical miles flown by a plane carrying 250 passengers.
However, it is not known how much extra energy, fuel and carbon emissions will be released as a result of having more planes in the sky.
Nor is it clear how much the reduction in fuel burn and costs created by causing passenger planes to make fewer stops would offset those used by the individual, heavy refuelling jets.