Passengers on select United Airlines flights will be flying in eco-friendly fashion. The airliner just completed the first-ever passenger flight using fuel made from algae. The flight from Chicago to Houston used a blend of petroleum-based jet fuel and biofuel made from genetically modified algae that feeds off plant waste and produces oil. The fuel, called Solajet, is provided by renewable oil and byproducts company Solazyme. United also agreed to buy twenty million gallons of the eco-friendly jet fuel from Solazyme every year. United officials say if sustainable biofuels are produced on a large scale at an economically viable price it can one day play a meaningful role in powering everyone’s trip on an airline.

The biofuel flight is part of the airline’s Eco-Skies program. United also operates more than 3,000 alternatively fueled or zero-emission ground vehicles. Pilots have been trained to use innovative flight techniques including continuous descent or tailored arrivals and using only one engine while taxiing to save fuel. The airline is also increasing the use of ground power instead of aircraft engines to move aircraft from gate to gate.

Alaska Airlines is another airline making eco-friendly decisions. The airline this week started using a biofuel blend made from recycled cooking oil. Airline officials say the 20 percent biofuel blend will help reduce carbon dioxide emissions by 10 percent. The U.S. Department of Defense is also testing biofuels on helicopters and marine vessels. The efforts are all part of the Obama administration’s policy aimed at transitioning away from fossil fuel dependence to cleaner energy sources.