Major airlines have committed to eliminating their net carbon emissions by 2050 even as they expect a fivefold increase in annual global passengers over the same period. To meet that ambitious goal, they’ve touted the potential of sustainable aviation fuel, or SAF, a product that is chemically identical to kerosene but more environmentally friendly. Until technologies such as batteries or clean-burning hydrogen are commercially viable for powering large aircraft, which could take decades, SAF is the industry’s best option for getting greener. Yet, for now, the alternative fuel is used only rarely in commercial flights. Its limited adoption is a result of two interconnected challenges: SAF is expensive for airlines to purchase, and production volumes remain constrained. SAF makes up only about 0.1% of the global aviation fuel supply. Some carriers are blending small amounts of it with jet fuel on certain flights. Yet the largest carriers are keen […]