Airbus will next year launch a further round of flight tests under its fello’fly initiative as it bids to bring the fuel-saving Wake Energy Retrieval (WER) concept into commercial service in the first half of next decade.
Test flights carried out by Airbus in 2021 showed that fuel-burn reductions of up to 5% were possible from WER in which the trailing aircraft in a two-ship formation – spaced around 1.2nm (2.2km) apart – benefits from the uplift generated by the preceding jet.
Recent flight trials within the EU’s Single European Sky (SESAR)-funded GEESE project, dealing with the air traffic management (ATM) aspects of WER operations, validated the feasibility of the aircraft rendezvous process, but Airbus is also seeking to evaluate additional aspects of formation flying.
While the 2021 sorties were performed using specific flight-test equipment, the airframer next year plans to test a solution “compatible with equipment that is onboard our customers’ aircraft in order to confirm its feasibility”, it says.
Additionally, the flights will “collect more data about vortex aerodynamics”.
Airbus intends to use its own test fleet for the studies, noting that the evaluation of WER operations using commercial flights will only be possible once the concept has gained regulatory approval.
But its own internal research and development activities are being supported by the work carried out through GEESE, a €10 million ($11.7) million) project that began in 2023.
GEESE saw Airbus and its partners – Air France, Delta Air Lines, French Bee, and Virgin Atlantic, plus AirNav Ireland, DSNA, Eurocontrol and NATS – conduct a series of eight pairing flights using A350s over the North Atlantic between September and October 2025.
The goal was to show that the operational concept “is a feasible and safe method to guide two aircraft to meet at a precise time and place” under real-world conditions.
Bringing the two aircraft together is a four-step process that is begun by the Airbus-developed Pairing Assistance Tool (PAT) which computes the new aircraft trajectories and shared rendezvous instructions in real-time.
Those details are then accessed, through a Eurocontrol interface, by airline dispatchers, flightcrew and air traffic control “to ensure operational acceptability”.
Under the third step, one of the paired flights then changes its planned route to join the other. At the final stage, both crews activate a cockpit function, committing the aircraft to arrive at the rendezvous at a predetermined time.
During the trials, vertical separation was maintained, says Airbus. It has not disclosed which carrier was paired with which, noting that “the airlines worked with each other to determine the best options based on their schedules”.
However, an image released by Virgin shows one of its services, bound for New York’s JFK airport, converging with a Delta flight to Atlanta.
GEESE runs until May 2026 and will be succeeded by a second phase following recent SESAR approval for a follow-on project.
This will continue working on how to integrate the WER concept into the broader ATM ecosystem and will widen “the feasibility demonstration to new airlines, new airspaces and new traffic flows”, says Airbus. Flightcrew procedures will also be matured under the planned phase two activity.
Airbus says commercial deployment of WER operations will likely be “in the first half of the next decade”.
But it cautions that this timeline is “based on the testing and certification process, which can and should take some time”.
