This article is based on an official press release from Airbus.

Airbus and Partners Validate Critical “Rendezvous” Phase for Wake Energy Retrieval

On December 11, 2025, Airbus announced the successful completion of a pivotal series of flight trials designed to validate the operational feasibility of Wake Energy Retrieval (WER). Conducted under the SESAR Joint Undertaking project known as “GEESE” (Gain Environmental Efficiency by Saving Energy), these trials mark a significant step toward reducing aviation emissions through formation flying.

The trials, which took place over the North Atlantic Ocean between September and October 2025, involved a massive cross-industry collaboration including four major airlines and multiple Air Navigation Service Providers (ANSPs). According to the announcement, the primary goal was to validate the “rendezvous process”, the complex procedure required to guide two commercial aircraft to a precise meeting point in transatlantic airspace safely.

While the concept of flying in a leader’s wake to save fuel has been theoretically proven, the logistical challenge of coordinating two distinct commercial aircraft flights to meet mid-air has been a major hurdle. These recent trials successfully demonstrated that current air traffic management systems can handle this coordination without compromising safety.

The Science of “Fello’fly”

The initiative, originally launched by Airbus as the “fello’fly” demonstrator in 2019, draws inspiration from biomimicry, specifically the flight patterns of migrating geese. In this operational concept, a “follower” aircraft positions itself approximately 3 kilometers (1.5 nautical miles) behind a “leader” aircraft.

The physics behind the concept rely on the wake vortices created by the leading plane. These vortices contain smooth updrafts of air; by “surfing” these updrafts, the follower aircraft requires significantly less engine thrust to maintain lift. Airbus data indicates that this technique can reduce fuel burn and CO2 emissions by up to 5% for the follower aircraft on a long-haul journey.

Validating the 4-Step Rendezvous

The trials conducted in late 2025 did not involve the actual wake-surfing phase but focused entirely on the setup: getting the planes together. According to the project report, the partners validated a specific four-step process:

1. Calculation: The Airbus Pairing Assistance Tool (PAT) computes optimized trajectories and rendezvous instructions in real-time.
2. Assessment: Airline dispatchers, flight crews, and Air Traffic Control (ATC) collectively assess the proposed trajectories using the EUROCONTROL Innovation Hub interface.
3. Adjustment: One of the participating flights alters its planned route to converge with the other.
4. Commitment: Both flight crews activate a cockpit function to commit to arriving at the meeting point at the exact, predetermined time.

This structured approach ensures that vertical separation and regulatory compliance are maintained throughout the maneuver.

A Cross-Industry Effort

The success of the GEESE project relies heavily on industry-wide standardization. The trials involved eight commercial flights and a diverse roster of partners. Participating airlines included Air France, Delta Air Lines, French bee, and Virgin Atlantic. On the navigation side, the trials were supported by AirNav Ireland, DSNA (France), NATS (UK), and EUROCONTROL.

Notably, the GEESE project includes Boeing as a partner, highlighting a rare instance of cooperation between the two major airframe manufacturers to establish a unified standard for formation flying. Other technical partners include Indra, ENAC, CIRA, and Frequentis.

AirPro News Analysis

The validation of the rendezvous process represents a strategic shift in how the aviation industry approaches decarbonization. While hydrogen and electric aviation propulsion technologies require massive infrastructure overhauls and new airframe designs, Wake Energy Retrieval utilizes existing aircraft and navigation infrastructure.

By focusing on software, data sharing, and procedural changes, WER offers a potential “quick win” for sustainability. The involvement of competing airlines and manufacturers suggests a consensus that operational efficiencies, like formation flying, must be standardized globally to be effective. The primary challenge remains regulatory: proving to safety authorities that commercial jets can fly closer than standard separation rules currently allow. The successful completion of these rendezvous trials is a foundational step in building that safety case.

Historical Context

The journey toward commercial formation flying has been methodical. Following the launch of the “fello’fly” demonstrator in 2019, Airbus conducted a landmark long-haul demonstration in November 2021. During that test, two Airbus A350s flew from Toulouse to Montreal maintaining a 3-kilometer separation.

The follower aircraft saved over 6 tons of CO2 on the trip, proving the physical fuel-saving potential.

The transition from the 2021 technical demo to the 2025 operational trials signifies the movement from “can we do this physically?” to “can we schedule this commercially?” The GEESE project is scheduled to continue until mid-2026, with the aim of mapping out full WER operations for both transatlantic and continental flights.

Sources

• Airbus
• Airbus / GEESE Project Reports