Currently, aviation accounts for 2-3% of global carbon emissions. That is significant but not insurmountable. The trouble is that aviation emissions are deep in a bucket marked “hard to abate.” Basically, that means aviation, like cement, steel, and a handful of other critical pieces of the economy, relies heavily on processes that we can’t decarbonize without lots of innovation, investment, and time.
Which is not to say that significant reductions aren’t available now. Erik Moreno Nielsen, Head of Sustainability at Goodwings, estimates a substantial chunk of aviation emissions could be avoided without the need for new technological breakthroughs: "If all currently available strategies were deployed at scale today, aviation's CO₂ emissions could plausibly be cut on the order of 25-35% versus a business-as-usual trajectory."
We’ll return to how voting with our wallets can boost low-carbon aviation later on. First, the longer view: a look at the nascent technologies that could, in time, make truly zero-emission flight a reality.
Battery electric
We already know how to decarbonize ground transportation: electrify all the cars and trucks. Why not do the same for jets and planes?
That prospect is quite a lot more complicated. Electric flight is a reality already, albeit modestly so: Companies like Pipistrel and Eviation are flying small electric demonstrators. These models are already being used to train pilots. So, electric aviation does have potential, but so far can only serve niche applications. The core problem is physics. Current lithium-ion batteries deliver at best 300 watt-hours per kilogram. Jet fuel? About 12,000. Even next-generation solid-state batteries, which promise improvements, won't come close to matching the energy density aviation currently demands. Batteries are also heavy, which compounds the problem: More weight requires more energy, which requires more batteries, which adds more weight. Given those challenges, the outlook is surprisingly optimistic for electric aviation at the regional level. Small commuter aircraft (think 9 to 19 seats) could start to appear between 2028 and 2031. Medium-sized planes with greater range might follow between 2033 and 2040. Long-haul? That's a different challenge entirely.
Hydrogen
Hydrogen offers enough energy density to power short- and medium-haul flights. If that hydrogen is "green" (produced via electrolysis powered by renewables) it could mean carbon-free, cross country flights for full-size passenger jets.
The catch is that we're starting from scratch. Unlike SAF (see below), current aircraft fleets are incompatible with hydrogen fuel. Liquid hydrogen has to be stored at -253°C in cryogenic tanks, which means redesigning aircraft from the ground up. Wings, fuselages, fuel systems, all of it has to change. Airbus has plans to bring a hydrogen-powered commercial aircraft to market between 2040 and 2045. And, even then, it will take time for a hydrogen-fueled design to replace the tens of thousands of planes in the global fleet. Then there's the fuel itself. Green hydrogen production exists, but not at scale, and not at a price that makes economic sense for aviation. Airports would need entirely new fueling infrastructure (cryogenic storage, specialized trucks, redesigned gates). It's a system-wide overhaul that would need to be in place anywhere hydrogen planes operate.
Still, the timeline is firming up. Short- and medium-range hydrogen aircraft could enter commercial service between 2033 and 2040. How long it might take the infrastructure and fuel supply to scale up to the point it can make a significant impact is another matter.
e-SAF/Synthetic fuels
Electro-sustainable aviation fuel (e-SAF) is the most elegant solution on paper. Combine green hydrogen with captured CO₂, run it through a chemical process, and out comes synthetic jet fuel that's chemically identical to what's already in use. No new aircraft designs. No airport redesigns. A drop-in replacement.
The technology works, but scaling is the sticking point.
Making e-SAF is energy-intensive. You need green hydrogen, which itself requires vast amounts of renewable electricity. You need CO₂ capture, which is still expensive and limited in scope. String it all together and the production costs are punishing: ten times the price of conventional jet fuel, sometimes more. That's why mandates matter. The EU's ReFuelEU aviation regulation requires 1.2% e-SAF blending by 2030, rising to 5% by 2035 and 35% by 2050. These quotas are designed to create demand, which should drive investment, which should eventually bring costs down. Eventually is the operative word. For now, e-SAF remains technologically proven but commercially nascent.
What We Can Do Now
The technologies above are promising. But they're also years (and sometimes decades) away from meaningful deployment. And carbon in the atmosphere can last for centuries: Emissions today matter just as much as emissions tomorrow.
So what can we do right now to reduce aviation's carbon footprint?
A big part of the answer is conventional bio-SAF: sustainable aviation fuel made from biological feedstocks like used cooking oil, agricultural residues, forestry waste, and dedicated energy crops. Unlike e-SAF, bio-SAF is commercially available today. It's already being blended into flights at airports around the world, from Amsterdam to San Francisco.
Like e-SAF, bio-SAF is a drop-in fuel. It can be mixed with conventional jet fuel at ratios up to 50% without any modifications to aircraft or fueling infrastructure. From a technical standpoint, it works, and it’s substantially less expensive than e-SAF.
However, cost remains a major obstacle. Bio-SAF currently runs three to four times more expensive than fossil jet fuel, depending on the feedstock and production pathway. As fuel is already one of the largest contributors to the price of flying, that’s a premium few are eager to pay. Relatedly, Jolanda Stevens identifies two factors as the primary bottlenecks KLM faces when scaling up SAF blending today: the price premium and slow consumer uptake. Nevertheless, Air France-KLM managed a 2.9% bio-SAF share in 2025 and is targeting up to 10% by 2030, well ahead of EU mandates.
Then there's scale. Global aviation consumes roughly 350 billion liters of jet fuel annually. Current bio-SAF production is a tiny fraction of that (around 1.3 billion liters in 2024). Production can grow, but there are real limits to how much waste cooking oil and agricultural residue exists. Still, when it comes to bio-SAF, plenty of room for sustainable scaling is there to be had. It is simply the most readily available solution for reducing per-flight climate impact today, and that immediacy matters.
The road to net zero
Aviation emissions remain stubbornly hard to abate. There's no silver bullet, no single technology that will cleanly solve the problem by itself. Our best option, then, is to maximize current solutions and continue making progress where we can. Service providers can do so by facilitating SAF purchases as much as possible, passengers can ensure they show their support for lower-carbon travel by electing SAF whenever they fly.
Beyond currently available solutions, the road to net-zero aviation leads through uncharted territory. Jolanda Stevens says that KLM is taking a multi-pronged approach: "We do not believe that a single solution will be sufficient to achieve the sector's ambitious climate goals.” For that reason, they’re embracing a portfolio approach: “supporting SAF production and uptake, improving operational efficiency, investing in fleet renewal, and collaborating with industry partners on breakthrough technologies." KLM has been an early mover on those breakthrough technologies, partnering with startups like ZeroAvia on liquid hydrogen demonstrator flights and working with Elysian Aircraft and Conscious Aerospace to refine electric aircraft concepts. The support of an established industry player could make all the difference to the development of these early-stage innovations.
KLM partnered with E-Flight academy on a two day flying tour with the Pipistrel Velis Electro.
The danger isn't that there are no answers. It's that we treat the complexity as an excuse for inaction. Aviation won't decarbonize overnight, but every percentage point matters. Every ton of carbon avoided matters. And every investment made today helps shape the aviation system of tomorrow.
If you want to know more about how you can cut travel emissions at your organization, join the movement to #MoveTheTravel.
