One rancher’s beef fat is now another man’s jet fuel.

According to Texas Public Radio, more and more biofuel producers are turning to farmers, ranchers and meatpackers to turn their byproducts, like beef fat, into renewable fuels like those used in jets and diesel-running vehicles.

Sugarcane, corn, industrial sweet potatoes and sugar beets, which are all biomass feedstocks, can be made into liquid fuels, heat, power and/or bio-based products. Agricultural residues like wheat straw and orchard prunings, food waste and animal byproducts like tallow, fish oil and manure can also be used to create renewable fuels.

Methane, a greenhouse gas, is also captured from manure and foods as they decompose.

United Airlines has reportedly already purchased 15 million gallons of jet fuel made from beef tallow for its Los Angeles to San Francisco flights. They’ve also taken it another step forward and have invested millions of dollars in a company that will use household garbage for its fuel feedstock.

United isn’t alone. FedEx, Southwest Airlines and UPS have also jumped on board and purchased jet fuels and diesel made from renewable resources.

Secretary of Agriculture Tom Vilsack says it’s a tremendous opportunity.

“I have no hesitation in telling you that we will have plenty of feedstock. The challenge is figuring out how to do it, where to do it, and the most efficient way region to region to do it, and using the feedstock that makes the best sense for that particular region,” Vilsack said.