We have said it before: Attempting to predict the future is an awful business. If you are right, it seems obvious in hindsight, and if you’re wrong, you’re an idiot. Anyway, I cannot help myself. So let’s start with last year’s reading of the tea leaves:

1. First fleet-wide testing: In 2024, we will see the first airline(s) testing contrail management on their entire fleet. This means analyzing all their flights daily to single out those few flights that can easily be diverted to save thousands of tons of CO2e. This will also give us a better understanding of the costs of managing contrails.

   RESULT: 🛑 Nah, we haven’t really seen fleet-wide testing in 2024 - at least not publicly. Dear reader, please correct me if I’m wrong!

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2. Airline involvement will double: We will see many more airlines getting involved with contrail management – or at least acknowledging the problem, especially in Europe, where all airlines must report their non-CO2 emissions – including contrails – from 2025. At Blue Lines, we track these frontrunners in our Contrail Airline Index. At the time of writing, there are 17 airlines in the index. By the end of the year, I predict this number will double.

   RESULT: ✅ Yes, this actually did happen. In the first half of 2024, more airlines went public on their contrail mitigation efforts, and the Contrail Airline Index went from 17 airlines to 35. Nothing much has changed over the past 6-8 months, though.

3. First public contrail campaign: We will see an airline, airport, or other organization launch the world’s first public contrail campaign. This could be an informational or marketing campaign announcing an airline's total commitment to managing the warming from contrails. I am excited to see who is going to be first.

   RESULT: 🟡 It wasn’t everywhere, but T&E launched a small contrail awareness campaign in parallel with the release of their well-researched contrail report in November 2024.

1 1/2 hits and 1 1/2 misses. Here’s what the crystal ball is telling us for 2025:

1. Corporations will want better contrail warming estimates. For many large software and consulting companies, their Scope 3 emissions from air travel are some of their highest emissions. What companies are doing now to also account for the non-CO2 impacts of air travel (including contrails) is multiplying their CO2 emissions by a factor of 1.7 or 1.9. However, with contrail prediction models and accurate corporate travel data, it should be possible to calculate the warming created by each flight taken by an employee and get much more actionable data.

2. The EU will sponsor at least one new contrail avoidance trial. I am not talking about the ongoing big EU-supported projects like CESAR or CONCERTO, but the EU’s Innovation Fund has specifically requested contrail / non-CO2 projects they can support. In 2024, a handful of airlines got together with flight planners, tech companies, and scientists to form a consortium looking to do thousands of contrail avoidance flights over the next years. The project was denied funding, but hopefully, someone will be successful in 2025.

3. New climate organizations will start focusing on contrails. Several climate or policy nonprofit organizations focusing on transportation are involved in contrail management work. However, many - more general climate-focused - NGOs don’t have their eyes open for this climate opportunity yet (I am looking at you, Greenpeace). Maybe one or two new organizations will get involved.

Okay, now I will stop making up stuff and stay with the facts. We promise to follow up on the predictions in 2026.

✈️🌍 Registration is now OPEN for the Copenhagen Contrail Conference! 🔥📅

Contrails are one of aviation’s biggest climate challenges—but solutions are within reach. At #CopenhagenContrails, we’re bringing together the brightest minds from academia, the aviation industry, tech companies, and civil society to turn knowledge into impact.

🚀 Join us on March 25-26, 2025, to explore:

✅ Practical solutions for reducing contrail warming

✅ Insights from leading contrail experts across sectors

✅ Collaboration opportunities to scale up action

📍 Scandic Copenhagen, hotel in Copenhagen, Denmark

⚡ Limited spots available!

🌐 Register now at copenhagencontrails.org.

Go to Blue Lines’ educational website to explore contrails in depth.

(As regular readers of the Blue Lines newsletter know, contrails are the thin white streaks that airplanes sometimes leave behind in the sky, created from water vapor and engine soot. Some of these condensation trails can spread out and form high-altitude ice clouds (cirrus), which reflect some of the sun’s energy back into space while also trapping outgoing energy in the atmosphere, leading to a net warming of our planet equivalent to 1-2% of human-induced global warming. However, studies and trials indicate that it is relatively simple to avoid most warming contrails by flying around areas in the atmosphere that are prone to contrails. This climate solution—often referred to as contrail management or contrail avoidance—is what Blue Lines advocates for and hopes to see implemented globally.)

See you soon.

Joachim Majholm,

Blue Lines