A Virgin Atlantic airliner making a test flight from London to New York became the first commercial aircraft powered by Sustainable Aviation Fuel (SAF) made by waste fats and plant sugars, a significant step in the effort to make commercial aviation greener.
Per the Washington Post (via gift link), the test flight was to ensure the feasibility of the use of SAF in commercial craft. Virgin Atlantic will not use the fuel because it is not yet commercially viable due to cost and availability, but the fuel used on this flight was calculated to result in 70% less carbon waste than it would have with standard aviation fuel.