https://jecats.copernicus.org/articles/ Combined list of the recent articles of the journal Journal of Environmentally Compatible Air Transport System and the recent discussion forum Journal of Environmentally Compatible Air Transport System Discussions en https://doi.org/10.5194/jecats-1-4-2026 Trade-off and risk in mitigation options for aviation Klaus Martin Gierens J. Env. Com. Air Transp. Sys., 1, 4, https://doi.org/10.5194/jecats-1-4-2026, 2026 Lessening of non-CO2 aviation impacts on climate is often accompanied by an increase of fuel consumption and emissions. Planning mitigation actions requires balancing the desired climate benefit against inevitable simultaneous climate damage. Due to uncertainty, statistical methods are needed to estimate the failure risk of concrete mitigation measures. This paper presents the required mathematics.  Mon, 07 Sep 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-16 A new ice crystal formation pathway in contrails generated by fuel cell propelled aircraft Dennis Hillenbrand and Simon Unterstrasser J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-16,2026 Preprint under review for JECATS (discussion: open, 1 comment) We study contrail formation behind future fuel cell-based aircraft fueled by hydrogen. Simulations show that, under certain conditions, small droplets can form via a process not occurring in current plumes. This can increase ice crystal numbers in contrails, boosting their climate impact. The effect is strongest in cold air and for high plume mixing rates with air. We suggest to decrease the mixing rate and exhaust humidity by technical design to reduce the climate impact of such aircraft. Tue, 25 Aug 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-14 Towards the implementation of climate-optimized air traffic in Northern Europe: Feasibility and airspace constraints of pre-tactical contrail mitigation Dennis Piontek, Kai Widmaier, Simon Kirschler, Joël Clément, Jacques Edeline, Jakob Smretschnig, David Antonello, Tarmo Pihlak, Simone Dietmüller, Sigrun Matthes, Katrin Dahlmann, Feijia Yin, and Christiane Voigt J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-14,2026 Preprint under review for JECATS (discussion: open, 0 comments) Model simulations were used to study all air traffic over Northern Europe during 16 days in 2023, following the European Union's planned framework (using CoCiP and aCCFs) for monitoring aviation’s non-CO2 climate effects. Small changes in flight altitude reduced the climate impact of contrails by 48 % while increasing the fleet-wide fuel use by only 0.4 %. The changes had only limited effects on air traffic density and aircraft spacing, showing that climate-optimized flight planning is feasible. Fri, 14 Aug 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-15 Assessing the climate mitigation potential of targeted SAF use in 2030 at Copenhagen Airport Roland Eichinger, Katrin Dahlmann, Volker Grewe, Benedict Enderle, Sven Maertens, Shravana Kumar, Christian Weder, Wolfgang Grimme, Leon Müller, Malte Niklaß, and Hannes Bruder J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-15,2026 Preprint under review for JECATS (discussion: open, 0 comments) Sustainable aviation fuels (SAFs) reduce the climate effect of contrail-induced cirrus cloudiness (CiC). We assess the climate-optimal SAF distribution for flights departing from Copenhagen Airport in 2030. We determine the potential climate benefit of 6 % available SAF by allocating it to flights with climatologically largest CiC climate effect to fuel use ratio. Targeted SAF use can here increase the CO2e benefit by 60 kt and enhance the CiC share in climate benefit from 20 % to almost 50 %. Fri, 14 Aug 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-12 A multi-physics Eulerian framework for long-term contrail evolution (MultiCon): Single plume analysis Amin Jafarimoghaddam and Manuel Soler J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-12,2026 Preprint under review for JECATS (discussion: final response, 3 comments) This study presents a multi-physics Eulerian framework for simulating the long-term evolution of aircraft contrails, a major contributor to aviation-induced warming. The model integrates advection, diffusion, ice-particle growth, turbulent settling, and habit evolution through a system of PDEs. Computationally efficient and calibratable against observations, it is well suited for large-scale contrail and radiative forcing simulations. Tue, 28 Jul 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-13 Can we achieve significant climate mitigation by optimising only for contrails? Jakob Smretschnig, Feijia Yin, Dennis Piontek, Joël Clément, Sergio Núñez Arribas, Katrin Dahlmann, Federica Castino, and Volker Grewe J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-13,2026 Preprint under review for JECATS (discussion: open, 1 comment) Commercial flights usually follow routes that minimise travel time and fuel use, but these routes are not always best for the climate. Using simulations of 4,000 flights forming condensation trails over northern Europe in 2023, we show that small altitude changes can reduce climate impact by 11 to 16% for only 1.2% more fuel. The benefits of avoiding warming from condensation trails outweigh the additional climate effect from nitrogen oxides and water vapour emissions. Tue, 28 Jul 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-1-3-2026 Concept of risk-aware contrail avoidance strategies Audran Borella, Cameron Steer, Nicolas Bellouin, and Olivier Boucher J. Env. Com. Air Transp. Sys., 1, 3, https://doi.org/10.5194/jecats-1-3-2026, 2026 Targeted contrail avoidance consists of rerouting aircraft to minimise the formation of warming contrails. However, current predictions of contrail climate impact are highly uncertain. In this study, we show that some reroutings that were predicted to be beneficial for the climate are in fact damaging it. We further demonstrate that the risk of unintentionally damaging the climate can and should be included in the decision-making of contrail avoidance. Fri, 10 Jul 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-1-2-2026 Improving reanalysis weather for contrail validation by incorporating satellite observations Scott Geraedts, Aaron Sarna, Susanne Rohs, Roger Teoh, and Kevin McCloskey J. Env. Com. Air Transp. Sys., 1, 2, https://doi.org/10.5194/jecats-1-2-2026, 2026 It can be difficult to know if a given aircraft made a contrail. Existing methods that can be applied to any aircraft either use numerical weather data or satellite observations. In this work we create a new method by combining weather data and observations together. By comparison to in-situ measurements we show that the new method is superior to previous methods. Fri, 10 Jul 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-10 Consolidating and stepping up aviation’s climate ambition: a comprehensive definition of a climate neutral air transport system Bram Peerlings and Ligeia Paletti J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-10,2026 Preprint under review for JECATS (discussion: final response, 2 comments) Aviation organisations have set varied climate goals, but misalignment, ambiguity and internal inconsistencies hinder real progress. This paper addresses this by proposing a comprehensive definition of a climate neutral air transport system: “air transport system of which the climate effects of all its greenhouse gases and non-CO2 effects throughout the entire life cycle of each element of the system is balanced”. Fri, 03 Jul 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-11 A machine learning approach for contrail detection and persistence prediction using airborne measurements from the ECLIF II/ND-MAX and ecoDemonstrator flight campaigns Ariadne K. Papamichou, Evanthia Kallou, Richard H. Moore, Holger Pfaender, and Dimitri N. Mavris J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-11,2026 Preprint under review for JECATS (discussion: final response, 3 comments) Contrails are thin ice clouds that may form behind aircraft, are responsible for about half of aviation's climate impact, and are hard to detect and predict. Using data from two flight test campaigns, we developed a tool that can be used with a camera mounted on aircraft to detect contrail formation and predict persistence in real time, with camera placement strongly affecting results. Using only this tool and onboard cameras, this lower-cost approach could help reduce aviation's climate impact. Wed, 24 Jun 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-7 Expanding spatial and temporal coverage of climate change functions: Assessment and comparison with aCCFs Christine Frömming, Volker Grewe, Sigrun Matthes, Simone Dietmüller, Patrick Peter, Katrin Dahlmann, and Patrick Jöckel J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-7,2026 Preprint under review for JECATS (discussion: final response, 2 comments) Aviation non-CO2 climate effects could be reduced through rerouting using Climate Change Functions (CCFs) and its surrogate aCCFs. This study expands CCFs regionally and seasonally and enables a comparison with aCCFs. ACCFs simplify complex processes but reproduce magnitudes and most gradients, though they underestimate variability compared to detailed CCF simulations and limitations to certain altitudes were revealed. The present study promotes future development of refined and extended aCCFs. Tue, 05 May 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-4 Efficacy of Scalable Airline-led Contrail Avoidance Tharun Sankar, Thomas Dean, Tristan Abbott, Jill Blickstein, Alejandra Martín Frías, Mark Galyen, Rebecca Grenham, Paul Hodgson, Kevin McCloskey, Alan Pechman, Tyler Robarge, Dinesh Sanekommu, Aaron Sarna, Aaron Sonabend-W, Marc Stettler, Raimund Zopp, and Scott Geraedts J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-4,2026 Revised manuscript under review for JECATS (discussion: final response, 4 comments) This randomized control trial provides evidence for the efficacy of airline-led contrail avoidance to reduce aviation's climate impact. By integrating ML forecasts into standard flight planning, dispatchers routed flights to avoid warming contrails. Satellite validation showed an 11.6 % overall reduction in contrails, increasing to 62 % for flights strictly following the optimized paths, all with no significant fuel penalty. Tue, 21 Apr 2026 22:34:25 +0200 https://doi.org/10.5194/jecats-2026-3 D-KULT: data and tools for routine eco-efficient flight operations Sigrun Matthes, Klaus Gierens, Björn Beckmann, Luca Bugliaro, Simone Dietmüller, Christine Frömming, Maleen Hanst, Sina Hofer, Julian Jene, Simon Kirschler, Carmen G. Köhler, Alexander Lau, Ralph Leemüller, Aline Liedtke, Max Mendiguchia Meuser, Patrick Peter, Vanessa Santos Gabriel, Ines Köhler, Gerd Saueressig, Linda Schlemmer, Jonas Sperling, Swen Schlobach, Ralph Schultz, Kristina von Sack, and Nathalie Waltenberg J. Env. Com. Air Transp. Sys. Discuss., https://doi.org/10.5194/jecats-2026-3,2026 Revised manuscript accepted for JECATS (discussion: closed, 4 comments) Operational strategies such as eco-efficient flight routing have potential to reduce aviation’s climate effect. A collaborative workflow integrating aviation weather forecasting, flight planning, air traffic control, and climate benefit assessment was developed and tested in D-KULT. Innovative developments demonstrate substantial progress on how to identify alternative trajectories but also highlight remaining challenges, including uncertainties in weather forecast and non-CO2 climate effects. Tue, 17 Feb 2026 22:34:25 +0100 https://doi.org/10.5194/jecats-1-1-2026 Editorial: A new sustainable aviation open-access journal Volker Grewe, Simon Blakey, Florian Linke, Sigrun Matthes, Jan Middel, Radu Mirea, Ayce Celikel, David Raper, Feijia Yin, and Xin Zhao J. Env. Com. Air Transp. Sys., 1, 1, https://doi.org/10.5194/jecats-1-1-2026, 2026 The Journal of Environmentally Compatible Air Transport System (JECATS) is a not-for-profit international scientific journal dedicated to aspects of the air transport system with a focus on the environmental implications. JECATS combines areas of aerospace engineering, fuels, environmental analysis, climate change, economics, aviation climate mitigation, circularity and policy analysis. It includes aviation transport-related aspects and environmental effects from local to global scales. Thu, 22 Jan 2026 22:34:25 +0100