The aviation industry may be one of the world’s most polluting industries, but at the very least there are a number of developments underway to reduce the industry’s carbon footprint.

Yesterday we wrote about one taking place in the Netherlands where aerospace engineers are designing a V-shaped airplane that uses 20 percent less fuel than today’s most advanced aircraft. Today, we present to you a new aviation solution: using a biofuel blend instead of regular jet fuel. This isn’t just an idea: it actually happened on a United flight from Chicago to Los Angeles on June 5th. Jet fuel accounts for roughly 99% of the carbon footprint of a flight, but with a biofuel blend, fuel emissions can be cut by 18 percent; pure biofuel can shrink emissions by as much as 60 percent.

Biofuel represents a superb solution to reducing the carbon footprint of flights as we make the long transition to electric planes. With that said, we’re still a way’s away from biofuel becoming an everyday reality in the aviation world. The supply of biofuel is growing, but limited, and technical constraints mean that the biofuel still has to be blended with regular jet fuel. But there will soon be more options.

New startups capturing CO2 emissions from power plants or directly from the air can also make new fuel with a dramatically smaller footprint. And now that one major commercial airline has started using biofuel, it may trigger others to follow suit.