Taylor Swift was pilloried online over the climate impacts of her private jet travel for the Eras Tour and to see Travis Kelce, now her husband, play in the 2024 Super Bowl. Her representatives said she paid to offset the tour-related emissions, but the uproar highlighted a bigger problem: Aviation is a serious source of carbon dioxide, and it’s tough to fix.

Flying accounts for roughly 2.5% of global carbon dioxide emissions, and that share is expected to rise as other sectors adopt cleaner power.

The trouble is that jet fuel is so good at what it does. It holds enough energy to fly a plane nonstop from New York to Singapore. Cleaners sources likes batteries can’t begin to match that range, and hydrogen fuel faces hurdles including fuel storage and transfer and the need for aircraft redesigns.

That leaves aviation with one top alternative for today: sustainable aviation fuel, or SAF.

Instead of pumping more oil from underground, SAF uses carbon already on the earth’s surface. Manufacturers — including two in the American West — are making the fuel from sources such as cooking oil, animal fats, oil-rich plants, farm and forestry waste, or even captured carbon.

“SAF really fits a need that we have today and long into the future,” said Ryan Spies, managing director of sustainability at Alaska and Hawaiian Airlines. “SAF is the answer because it’s a drop-in fuel. That means we don’t have to change our planes, we don’t have to change what’s happening at the airport.”

The fuel remains in limited supply and use — only 1% of Alaska Air Group’s fuel is SAF, for example — but efforts are underway to expand production and adoption worldwide.

Twelve’s captured-carbon approach

In tumbleweed country in central Washington, a startup called Twelve opened its AirPlant One facility last year and began commercially producing SAF from captured carbon dioxide this summer.

The site sits in an industrial stretch of Moses Lake in a largely agricultural area. Its neighbors include a fertilizer producer and battery materials manufacturer Sila. Low-cost, carbon-free hydropower has drawn businesses to the region, though data centers are creating competition for the energy.

To manufacture SAF, Twelve takes delivery of carbon dioxide that’s captured as a byproduct of ethanol production. The greenhouse gas is stored in a giant white tank. From there it’s pumped through insulated silver pipes that carry it through devices that remove oxygen and add hydrogen taken from water, producing the hydrocarbons that serve as fuel. The largely outdoor facility is shiny and new, with equipment stretching skyward.

The startup’s technology can make a variety of low-carbon products, including naphtha, a plastics precursor also produced at AirPlant One.

The site is designed to make up to 50,000 gallons of SAF, which is branded as E-Jet. The company is ramping up to that volume, said Nicholas Flanders, CEO and co-founder of Twelve.

“Even when we’re at that full capacity, there’s a lot more customer demand than we can make at AirPlant One,” he said. AirPlant Two, a much bigger facility that would make tens of millions of gallons a year, is already in development. Flanders did not provide a timeline or location for the site.

Old refinery finds a new purpose

About seven hours east of Moses Lake by car, Montana Renewables is producing SAF with a different approach. It makes the fuel at a century-old oil refinery that has been partially converted to renewable fuel and naphtha production.

“That’s the most economical way to to produce renewable fuels like SAF,” said Matt Upmeyer, vice president of commercial for Montana Renewables.

The facility uses feedstocks including used cooking oil, beef tallow from rendering plants and camelina, a lesser-known cover crop that helps farmers restore soil and also produces an oily seed.

Montana Renewables began making SAF in 2023, and by the next year was the largest SAF producer in North America, Upmeyer said, “which is a pretty cool stat.”

The company can produce 60 million gallons of SAF a year in Great Falls, Mont., and aims to reach 200 million gallons by the end of 2028.

That growth is significant, but the need is much higher. The U.S. government set a goal a few years ago of producing 3 billion gallons of SAF annually by 2030. A recent academic study involving researchers at Washington State University estimates the country could potentially reach 2.1 billion gallons by then. That total counts SAF from all U.S. producers, including Phillips 66, World Energy, Neste and LanzaJet.

By comparison, U.S. airlines use about 20 billion gallons of fuel a year, and that number is rising.

Cleaner fuel carries a premium

Cost is arguably the biggest hurdle to SAF adoption. The fuel is more expensive than traditional jet fuel, but the gap fluctuates because geopolitics moves oil prices. It should get cheaper as production scales, though demand will remain high.

Spies offered rough estimates for price comparisons. SAF made from fats, oils and greases — the most common form today — trades at less than double the price of jet fuel, he said. SAF from captured carbon, like Twelve’s, has the greatest environmental benefit, Spies said, but is “multiple times more expensive.”

Policy can help close the gap. The U.S. has used “carrots” such as a tax credit of up to $1.75 per gallon, created in 2022, but that was cut to $1 with President Trump’s return to office. Europe has opted for “sticks”: a requirement that 2% of jet fuel be SAF starting last year, which rose to 3.6% in the United Kingdom this year.

Customers are signing fuel purchase agreements, which can lock in prices and create demand that encourages more production. Alaska Airlines and Microsoft partnered with Twelve in 2022 to support its fuel’s development and use, helping create demand for the Moses Lake plant’s output.

Getting customers to sign these long-term deals “is really important for securing project financing,” Flanders said.

Measuring SAF’s climate benefits

While SAF is the best near-term fuel for reining in aviation emissions, it still produces carbon dioxide when burned. But unlike petroleum-based jet fuel, which releases carbon that would otherwise stay trapped underground, SAF recycles carbon already in circulation in plants, animals and the atmosphere.

And there are other strategies for curbing aviation’s impacts that can compliment SAF, including designing more efficient planes, preventing contrail formation, and using flight plans that reduce emissions.

Most SAF produced today provides an 80% reduction. By Twelve’s calculations, if a plane used straight E-Jet, it could slash the flight’s carbon emissions up to 90% compared with jet fuel (there are some carbon costs for production and transportation).

Twelve’s Flanders put the benefits in perspective.

“To have 90% lower emissions when you fly, that would mean taking a domestic flight would have the same emissions per passenger mile as taking the London Tube,” he said. With flying on par with taking the train, “it really can change the impact of aviation on the environment.

Sources and references

Interviews:

• Nicholas Flanders, CEO and co-founder of Twelve
• Ryan Spies, managing director of sustainability at Alaska and Hawaiian Airlines
• Matt Upmeyer, vice president of commercial for Montana Renewables
• Cody McNaughton, plant manager for Twelve’s manufacturing facility
• Michael Donaldson, director of environment, health and safety at Twelve’s manufacturing facility

Sources:

• “Sustainable aviation fuel is taking off. What is it, exactly?“, Canary Media, Nov. 21, 2024
• “Pragmatic assessment of meeting the 2030 U.S. sustainable aviation fuel goal,” Biomass and Bioenergy, March 2026
• “Europe Widens Its Lead Over US, Asia in Switch to Cleaner Jet Fuel,” Bloomberg, Aug. 13, 2026

The team at Seattle-based Nimbus Aerospace had planned to finish testing its quarter-scale prototype earlier in the summer, but struggled to schedule one of the few pilots skilled in remote-controlled flight.

“Not many people wanted to fly this thing,” said Adrian Groos, co-founder and CEO of Nimbus. “It was a $1 million-plus model that was significantly bigger than anything else most people have flown, as well as heavier.”

The startup is developing a hybrid-electric aircraft with high-lift wings designed to improve fuel efficiency. Nimbus plans to build a six- to eight-passenger aircraft with a 1,500-mile range that uses half as much fuel as a comparable conventional plane.

In June and August, the startup conducted two test flights of its NX1 prototype at the Pendleton Airport UAS Range in Oregon. The aircraft, which has a 15-foot wingspan and weighs 200 pounds, flew for 3 minutes 42 seconds in the first flight and 6 minutes in the second.

The tests achieved their goals of demonstrating the company’s manufacturing capabilities and the aircraft’s aerodynamics and stability, Groos said.

Nimbus has started engineering a full-scale prototype, with test flights targeted for 2028. The team is still deciding where to build the aircraft, considering Seattle against other locations around the country.

The ultimate goal is to begin delivering aircraft to customers in late 2030.

To get there, the team is working to navigate the Federal Aviation Administration’s certification process as smoothly as possible. The company has built a system called the ACT (AI Certification Tool) Platform to streamline and expedite FAA certification, and a former FAA deputy director of aircraft certification sits on the startup’s advisory board.

While the Nimbus product has a unique hybrid powertrain, components such as landing gear and lights use already-approved, pre-certified parts that will also be cheaper and easier to fix.

“We’re not trying to build a super novel design. That’s just a certification nightmare,” Groos said. “We’re trying to bring an aircraft to market that solves the needs that the people are asking for.”

And what customers want is a plane that burns less fuel and requires less maintenance, he added.

Aviation is one of the most difficult industries to decarbonize. It contributes 2.5% of the greenhouse gases emitted annually, but that percentage is expected to increase as other sectors go low-carbon and air travel increases. In addition to battery- and hydrogen-powered aircraft, sustainable aviation fuel, or SAF, is seen as the most promising solution for larger planes.

Washington state is also home to sustainable aircraft startup magniX, though others have shut down. Electric-aviation startup Zunum Aero and Outbound Aerospace folded, and ZeroAvia largely ceased operations in the state earlier this year, though it remains active in the United Kingdom. California-based Universal Hydrogen, which test-flew a hydrogen-fueled plane in Moses Lake, Wash., closed in 2024.

“People created products that weren’t really ready for prime time,” Groos said. That’s particularly the case for hydrogen-powered aircraft — the fuel is in limited supply and the path to certification is uncharted, he added.

Other companies in the hybrid-electric space include Heart Aerospace, Electra.aero and Ampaire.

Groos and Nimbus co-founder and Chief Technology Officer Akim Niyonzima met on LinkedIn and began working on a sustainable aircraft in 2023. The five-person team also includes Chief Marketing Officer Eno Oduok. The startup, a past Techstars participant, has raised about $4 million from an unnamed family office. The company hopes to add six engineers over the next year.

Nimbus is going to move its NX1 to the Pendleton Airport UAS Range hangar, where it will be displayed alongside the Airbus Vahana eVTOL, a prototype all-electric, single-seat aircraft capable of vertical take-off and landing.