Airbus Tests A350 Bird-Like Formation Flights To Save Fuel

Last week Airbus tested a ‘flock’ of A350s in a bird-like formation as part of its ‘fello’fly’ program. Airbus believes that flying aircraft one behind the other, a behavior seen in migratory birds, could result in significant fuel savings.

Airbus A350
Airbus is exploring the benefits of flying commercial aircraft in formation. Photo: Laurent Errera via Wikimedia Commons

Last week Airbus’s fello’fly program got underway with a two-aircraft test flight across the Atlantic. The European aviation giant hopes to explore the possibility of flying aircraft in formation in order to reduce fuel use. If the research program proves fruitful it could offer significant savings on both fuel costs and emissions. This would be a win-win for airlines as they attempt to find new ways to increase the efficiency of their operations.

Last week’s tests

According to tweets posted by A350Blog last week, Airbus conducted tests as part of the fello’fly program on Thursday and Friday. Thursday’s flight involved the MSN1 Airbus A350 prototype, which completed an 11-hour journey from Toulouse to Iceland to Greenland to Canada and then back to Toulouse.


This flight was presumably launched in order to gather information about the performance of an Airbus A350 flying in a standard single-aircraft formation. The following day a two-aircraft flight was launched. This time the prototype Airbus A350 flew in formation with a second Airbus A350 – An Airbus A350-1000 with MSN59.

Airbus has more fello’fly test flights in the works. Photo: Airbus

According to A350Blog, a similar series of test flights was flown back in 2016. While the first flight of this initial test series also involved A350 MSN1, the second test involved a formation flight led by an Airbus A380.

What does Airbus hope to achieve with the fello’fly test flights?

According to an article posted on Airbus’s website back in November, the manufacturer hopes its fello’fly program will “demonstrate the technical, operational and commercial viability of two aircraft flying together for long-haul flights.”

The program is one of many projects undertaken across many different industries that aim to explore the benefits of biomimicry – the practice of copying designs found in nature for the purpose of human technological advancement. In this case, Airbus believes there is potential for significant fuel savings if two aircraft are flown one in front of the other, mimicking the flight formations of migratory birds.

Airbus A350 Prototype
Airbus is using the A350 in its fello’fly test flights. Photo: Ken Fielding via Wikimedia Commons

In Airbus’s fello’fly tests, the two aircraft will be flying in formation with a separation of just 1.5nm, significantly less than the current five nm limit set out by the FAA. Airbus believes the tests could result in a 10-15% reduction in fuel burn in the follower aircraft. If the tests do show a practical reduction in fuel burn is possible, implementing the new dual formation would only really work on longer-haul flights.

Grouping aircraft in twos on busy routes would increase the likelihood of incidents if the new flight strategy is not monitored closely. It would also probably mean that aircraft have to wait to take off together, increasing logistical pressure on air traffic control and significantly increasing crowding at the airport terminals as passengers for multiple planes have to be coordinated together.


Leave a Reply

newest oldest most voted
RH Hastings

Why stop at two widebodies flying in formation? If they’re going the biomimicry route have a bunch, a skein. The first ones up can fly a bit slower til the rest show up…. or heck, just all take off at the same time all flapping their newly designed Airbus biomimicry… Read more »


This is all good but how does Airbus see airlines put this plan to practice? Do we have a “flock” of aircraft starting from Frankfurt to New York at the same time? Or do we have aircraft departing from different cities meeting at a single point to form a vee?


And the kerosene stink in aircraft no.2… maybe first class in no.1 and everyone else in no,2 !


This has been tried before in the USA. The difference is that Airbus are using a LIDAR to measure and find the up wash and the optimal position. This also has the advantage of having an outstanding wind shear warning sensor.


Or, a plane taking off from LGA and another one taking of at JFK can rendezvous shortly after takeoff and fly tandem across the Atlantic. They need not land at the same airport either, just split up as they approach their respective destinations.


Or hitch a ride with an already flying airplane.
Juno from one wing to another.

Frans Badenhorst

Very good idea. But birds do not fly behind each other in formation. Perhaps Airbus should study bird formations a bit more? The angle and distsnce behind the leading bird is the secret, just scale that up, perhaps?

Michael Mcpherson

Painfully ignorant people. Ridiculous comments with no basis in fact.
The real question is why not fly a jumbo A380? It’s not double the fuel and the whole formation thing is moot. I suppose for flights a cross the Atlantic landing, once crossed, at different destinations, it could have promise.


Well flying patterns like a flock of birds need more studies, but in simpler terms only the jet following behind will be the one saving fuel and what about the lead aircraft how can it impact on fuel savings for the lead aircraft, Secondly whatever the cost savings, they can’t… Read more »

Paul Proctor

Boeing did similar tests with C-17s a few years ago. I believe they used some form of technology to control spacing as well. Makes more sense when you are moving several aircraft with troops and/or equipment to a hot spot. I believe both sets of tests might indeed have promise… Read more »

warren trout

Nothing new to the military. I flew C130s in visual and instrument formation. As a retired airline pilot, I cannot even wildly imagine this working for an airline.


Saw four planes flying over Colorado in a formation at about 30,000 feet. Wish I could share the pictures I took of it. They were in a diamond formation, could of been military. Was really cool looking contrails.

Larry C

Couldn’t they save even more fuel by flying 1/3 fueled A350’s between Paris, PDL (Azores), and Gander on there way to NY or Chicago? Carrying around 150,000 pounds less of Jet-A has got to save some big $$$.


This could really save some fuel if the first aircraft towed the second aircraft across the Atlantic. They love to think out of the box in Toulouse. In 1993, the following was overheard in the Bleriot conference room in Toulouse – What if we took an A340 and added some… Read more »

E Steve K

To me nm means nanometer. That would be very close.


Military was trying this some time ago already…like close formation

Ravioliollie kaye

This isn’t really new. After 9/11, there were a few conversations about “bundling” flights all going the same general direction for security and fuel savings.

Steve H

It’s a novel idea, almost laughable but without people thinking out of the box, we as people would never have left the ground or done anything interesting, exciting or something that made things better for us.
It might work….it might not, but it’s worth a try anyway.