Delta Air Lines and Finnish renewable-fuels producer Neste have detailed a joint roadmap aimed at expanding sustainable aviation fuel availability, according to a feature published on Neste's website.

The piece frames the relationship as a multi-year effort covering supply-chain development, feedstock diversification and work toward higher SAF blend limits. It does not disclose new offtake volumes, contract lengths, or delivery dates beyond what the two companies have previously announced.

What the collaboration builds on

Delta and Neste have worked together since at least 2021, when Delta began purchasing Neste MY Sustainable Aviation Fuel for blending into the common fuel infrastructure at Los Angeles International Airport. LAX's hydrant system routes SAF-blended fuel to any participating carrier at the certified ratio, a pooling model that Delta's fuel team has cited as a way to scale SAF beyond bilateral procurement.

Neste remains the world's largest producer of renewable diesel and SAF, with refineries in Singapore, Rotterdam and Porvoo, Finland. Its commercial SAF is produced primarily through the hydroprocessed esters and fatty acids, or HEFA, pathway from used cooking oil, animal-fat residues and other renewable waste streams.

What SAF certification actually allows

Under ASTM D7566, SAF can be blended into Jet A or Jet A-1 up to 50%, with the resulting blend meeting D1655 specification. Neste's published, third-party-verified life-cycle assessment credits its SAF with up to 80% greenhouse-gas reduction on a well-to-wheels basis versus fossil jet fuel.

That figure is the one airlines use in Scope 1 reporting and in voluntary carbon disclosures. It also underpins regulatory frameworks including the EU's ReFuelEU Aviation mandate, which imposes rising SAF blending obligations at European Union airports from 2025 onward.

Why a Delta-Neste roadmap matters commercially

SAF carries a price premium over conventional jet fuel that industry participants have historically placed between two and four times, depending on feedstock, contract length and delivery point. Airlines manage the gap through corporate SAF programs, book-and-claim accounting, and federal or state incentives. Delta has set a target of sourcing 10% of its jet fuel from SAF by the end of 2030.

For a network carrier operating near Delta's scale, even modest SAF penetration reshapes both the unit cost base and the emissions footprint reported under emerging standards. Fuel is the carrier's largest variable operating expense, and SAF offtake has been co-financed through Delta's corporate customer and employee programs.

What remains uncertain

The Neste feature does not specify whether the roadmap introduces new U.S. airport supply points, expanded feedstock categories, or higher blend limits. Those details will determine whether the collaboration materially shifts gallons lifted rather than reaffirming existing channels.

ASTM International's SAF standards committee continues to evaluate alcohol-to-jet and power-to-liquid pathways, which would widen the feedstock menu beyond HEFA. The pace of those approvals, alongside pretreatment and refining capacity coming online outside Europe and North America, will shape how quickly any Delta-Neste expansion translates into additional volume at Delta hubs including Atlanta, Detroit and Seattle.

The next concrete test will be whether the two companies publicly anchor new offtake volumes, supply points or feedstock categories in their 2025 contracting cycle.