Contrail Trials
This is a list of past, current, and future contrail avoidance trials where airlines or air navigation service providers (ANSPs) are actively experimenting with avoiding climate warming contrails.
The list only contains trials that have been publicly announced, and we are excluding very small projects (less than 10 contrail avoidance flights)
If you think we are missing a contrail avoidance trial in our data set, please contact us here.
MUAC/DLR Contrail Avoidance Trial (2021)
EUROCONTROL’s Maastricht Upper Area Control Centre and DLR ran the first operational contrail-prevention trial in live European airspace. Controllers asked pilots to climb or descend ~2,000 ft to avoid forecast ice‑supersaturated regions during night hours. This is widely cited as the first real-world contrail avoidance trial at scale.
Organizations: DLR (German Aerospace Center), EUROCONTROL MUAC (Maastricht Upper Area Control).
KLM/SATAVIA Contrail Prevention (2022-23)
In 2022, KLM conducted its first contrail-avoidance test flight during the Aviation Challenge, followed in 2023 by a six-month operational trial running one day per week across European routes. The project focused on understanding real-world challenges: dispatch workload, crew coordination, and operational limits while manually adjusting flight plans shortly before take-off to avoid contrails.
Organizations: SATAVIA, KLM, KLM Cityhopper.
Etihad/SATAVIA Contrail Avoidance (2022-25)
Etihad Airways worked with tech company SATAVIA to pre‑plan routes and cruise altitudes that would avoid high‑impact contrail regions on selected long-haul flights. The airline ran weekly avoidance operations across its network and dedicated ‘EcoFlights,’ logging 20+ modified flights in intensive test weeks and then moving toward day‑to‑day integration. Etihad signed a multi‑year commercial agreement with SATAVIA to scale contrail prevention.
Organizations: SATAVIA, Abu Dhabi sustainability partners, Etihad Airways.
American Airlines/Google Research/Breakthrough Energy Trial (2023)
American Airlines pilots flew 70 test flights using AI-generated ‘contrail risk maps’ from Google Research and Breakthrough Energy. Altitudes and routing were adjusted on select flights to avoid predicted high‑warming contrails, then researchers verified outcomes with satellite imagery. The study found a ~54% reduction in contrails on treated flights, with a ~2% average fuel penalty, translating to ~0.3% across an entire airline fleet.
Organizations: Google Research, Breakthrough Energy, FlightKeys, American Airlines.
Delta/MIT Tactical Contrail Avoidance Development (2023-24)
A collaboration between Delta Air Lines and Massachusetts Institute of Technology developed a tactical contrail-avoidance tool that uses real-time weather and satellite inputs to identify and advise on altitudes and trajectories where persistent contrails would form. The system was tested in operational flight trials, aiming to give airlines a practical route to reducing non-CO₂ climate impact with minimal fuel penalty.
Organizations: MIT (MASC / Laboratory for Aviation & the Environment), Delta Air Lines.
SATAVIA DECISION X / Multi‑Airline Demonstrator (2023-24)
A 10-month trial led by SATAVIA, supported by the UK and European space agencies, analysed 65 commercial flights across 12 airlines and used advanced contrail-avoidance software to prevent more than 2,200 tonnes of CO₂-equivalent warming with minimal fuel penalty.
Organizations: SATAVIA, European Space Agency, UK Space Agency, Icelandair, Kenya Airways, Condor, SunExpress, KLM, Vueling, other airlines (12 total).
100 Flights Contrail Trial (2023-25)
The German ‘100 Flights’ initiative, set out to run ~100 contrail-optimized flights with Lufthansa Group and other German carriers. The trial combined forecasting, airline dispatch changes, and ATC altitude clearances from DFS/MUAC. Goal: build statistical confidence in both climate benefit and operational cost, and generate evidence for eventual policy incentives in German and EU airspace.
Organizations: DLR, DFS, EUROCONTROL MUAC, Jeppesen, PACE, Airbus, TUI, Condor, Lufthansa, DHL/European Air Transport.
CONCERTO ANSP-Led Trial (2023-26)
The CONCERTO project focuses on real-time contrail avoidance operations over Northern Europe. It integrates contrail forecasts directly into air traffic management systems, enabling ANSPs to test altitude and routing adjustments that minimize contrail formation while maintaining safety and efficiency. The project aims to bridge research and live operations, showing how contrail mitigation can be embedded into daily network management in Europe.
Organizations: DLR, DWD, TUDelft, Borealis Alliance, Thales, Icelandair, PPS, and others.
CICONIA Airline-Led Trials (2024-26)
The CICONIA project focused on integrating contrail-avoidance intelligence into airline dispatch and European ATM. Participating airlines Air France, Swiss, and easyJet worked with ANSPs and the Network Manager to test altitude/routing changes that avoid contrail areas while respecting safety and capacity constraints. The project is explicitly about mainstreaming contrail mitigation into day‑to‑day European network operations.
Organizations: Airbus, DSNA, Météo-France, EUROCONTROL MUAC, DLR, Air France, Swiss, easyJet, Klima Consulting, and others.
Thales/Amelia Trial (2024-)
Regional French airline Amelia, together with Thales, began its contrail avoidance collaboration by targeting flights between Paris and Valladolid in 2024. In 2025, contrail avoidance was progressively deployed to a larger number of Amelia departures, eventually aiming for full network inclusion.
Organizations: Thales, Amelia.
MUAC/Google Trial (2024-25)
The MUAC–Google trial was testing how artificial intelligence can help air traffic controllers avoid climate-warming contrails. Using Google’s satellite-based image recognition and prediction tools, the trial analyzed when and where contrails form and gave quick feedback on flights that successfully avoid them. This would test whether AI tools can be safely integrated into daily air traffic operations to make contrail mitigation routine.
Organizations: EUROCONTROL MUAC, Google Research, Breakthrough Energy.
American Airlines North-Atlantic trial (2025)
In early 2025, American Airlines conducted was one of the largest operational contrail avoidance trials to date. Over 17 weeks, contrail forecasts were integrated into the airline’s flight-planning software for more than 2,400 transatlantic flights. Flights that followed contrail-optimized routes reduced observable contrail formation by about 62%, with no statistically significant increase in fuel use.
Organizations: Google Research, Contrails.org, American Airlines, Flightkeys, and Imperial College London
A4Climate (2025-29)
A4Climate is a European project to reduce the climate impact of contrails by turning atmospheric science and forecasting into practical flight-planning tools. It includes large-scale airline trials where 400+ flights are optimized to avoid contrail-forming regions, measuring climate benefits and operational trade-offs to support routine mitigation and future EU policy.
Organizations: DLR, Flightkeys, TUIfly, DWD, and Contrails.org.