From Fryer to Flight: How United Cargo Is Helping Scale Sustainable Aviation Fuel

If you told someone a century ago that airplanes could one day fly on used cooking oil, they might have laughed.

Today, it’s actually a part of aviation’s path forward.

Through sustainable aviation fuel (SAF)1, materials like used cooking oils, agricultural waste, and other renewable resources can be transformed into jet fuel capable of powering modern aircraft. While the science behind SAF is complex, the mission is simple: reduce aviation’s carbon footprint while keeping global commerce moving.

At United, that mission has become a major focus, with United Cargo customers helping drive early adoption.

“Our goal is to replace conventional jet fuel with sustainable aviation fuel by 2050,” said United’s Senior Manager of Environmental Sustainability Andrea Ayala. “That’s incredibly ambitious because the market isn’t producing SAF at that scale yet.”

The challenge isn’t just producing SAF. It’s producing enough of it.

Today, SAF can cost two to four times more money than traditional jet fuel, and global supply remains limited. Scaling it requires investment, infrastructure and perhaps most importantly, demand. That’s where United Cargo customers come in.

A natural fit for United Cargo

Every day, United Cargo moves tons of shipments across its global network. Each pallet, container and shipment adds weight to the aircraft, and with that weight comes fuel consumption.

Because of that scale, cargo quickly became a natural place to help build the SAF market.

“When you think about the millions of kilos we move every year, you can also think about how much fuel is required to move that freight,” said Courtney Buckwalter, who supports sustainability initiatives within United Cargo. “So, cargo naturally became a big part of the SAF program.”

Early on, several strategic customers stepped forward to participate, helping create the demand needed to expand SAF production.

“They were really the drivers at the beginning,” Buckwalter said. “These companies wanted to create that demand and help build the market.”

Using waste to make SAF

Scaling sustainable aviation fuel isn’t easy. Converting fuel facilities to produce SAF can cost hundreds of millions of dollars, and producers need confidence that demand will grow. But sometimes big progress starts with simple ideas, like using yesterday’s frying oil as a feedstock to make SAF that is then blended into conventional jet fuel for a flight.

“I like to say I help make planes fly with French fry oil-based SAF blends,” Ayala said. “It’s an over-simplified way to explain it, but the idea that waste materials can help power aircraft is one of the coolest parts of this work.”

Turning that idea into reality takes partnership. In 2021, United launched the first corporate SAF program, allowing companies to support SAF purchases connected to their travel or cargo shipments.

“We’re not only investing in SAF producers,” Ayala said. “We’re investing in the entire ecosystem, from the building blocks of the fuel to technologies like carbon capture that could support future fuels.”

United also created the Sustainable Flight Fund, which supports start-ups focused on decarbonizing air travel and its associated energy supply chains, including through research and production, and technologies associated with SAF. The fund has raised more than $150 million, bringing together partners across industries and even other airlines.

What once powered a deep fryer can now help power a flight, and with continued collaboration across the industry, that small but powerful idea is helping move aviation forward.

Building the market together

Turning yesterday’s frying oil into tomorrow’s jet fuel takes more than chemistry. It is the same spirit of innovation and partnership that has shaped United Airlines for a century.

“We’re still helping build the market,” Ayala said. “Creating certainty around the environmental value of SAF is key to supporting long-term investment and scaling production.”

For United Cargo, customers are helping turn momentum into progress. Early adopters helped create the initial demand for SAF, proving that sustainability initiatives can grow when airlines and shippers work together.

“Our customers are helping create something new,” Buckwalter said. “They’re helping build the demand that will allow sustainable aviation fuel to scale across aviation.”

That collaboration is helping turn an unlikely idea into real momentum. What might start as waste materials can eventually help power a flight halfway around the world. Simultaneously, these collaborations are helping shape what the future of flight may look like in the next century: one where innovation, partnership and sustainability efforts travel together.