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Travellers could soon fly non-stop from Europe to Australia - or even further - under plans to change how planes use fuel.

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 to five passenger planes, located at various points along flight routes.

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A collaborative team of scientists from nine European universities has designed its Cruiser-Feeder concept that would allow planes to refuel in mid-air (illustrated). The system would involve a refuelling plane carrying enough kerosene to top 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 offload 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. 

Air-to-air refuelling would only be carried out near main airways and away from inhabited areas.

It is a technique already used by the military, for example, to refuel state aircraft.  

The civil concept was developed as part of a wider project called Research for a Cruiser Enabled Air Transport Environment (Recreate).  

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.

MailOnline has contacted the researchers to learn more.  

The scientists have spent the last three years studying the feasibility of civil air-to-air refuelling operations similar to those used for military aircraft. 

Researchers test air-to-air refuelling of passenger aircraft

As the passenger plane approaches, the refuelling jet could take off, fly beneath the plane before connecting specially-designed and made fuel tanks and pumps at targeted locations on the plane (illustrated). It would then offload the required amount of kerosene before disconnecting and returning to the ground

The civil concept was developed as part of a wider project called Research for a Cruiser Enabled Air Transport Environment (Recreate). Air-to-air refuelling (illustrated) would only be carried out near main airways and away from inhabited areas. It is a technique already used by the military

They propose that passenger flights could take off with less fuel and retank once they reach an altitude of 33,000ft (10,000 metres). 

This would also reduce noise pollution near airports since planes make more noise the heavier they are at take-off, said Leonardo Mafriani from ZHAW.

The system would also allow for non-stop flights between destinations as far apart as Zurich and Sydney.

The researchers have already tested the concept using simulators to determine that the project is technically possible.

The researchers 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 could be reduced by up to 23% for every 6,000 nautical miles flight with a payload of 250 passengers

The system would also allow for non-stop flights between Europe and Sydney, for example, and the researchers have tested the concept using simulators (pictured). 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

The Recreate project also includes a second, more radical proposal which involves building an air-metro system, with giant aircraft circling the globe, and smaller 'feeder aircraft' unloading passengers, luggage and waste midair, transporting them to destinations along the way.

The researchers acknowledge though that for the second part of the project 'neither airworthiness nor acceptance of the idea by the general public is within sight.'

The concept has been developed by experts from NLR, Amsterdam, DLR Braunschweig in Germany, FOI in Sweden, TU Munich, TU Delft, Queen's University Belfast, ZHAW in Zurich, Nangia Research Associates and NRG in The Netherlands.