On Wednesday, December 1, 2021, a United Airlines flight with over 100 passengers took off from Chicago’s O’Hare International Airport to Washington D.C. on the first passenger flight with 100% sustainable aviation fuel.

The 737 MAX 8 aircraft used 500 gallons of green fuel in one of its engines and an equal amount of regular jet fuel in the other engine. Airlines are allowed to use a maximum of 50% of green fuel on any flight.