United and Honeywell announced a joint multimillion-dollar investment in Alder Fuels, known for producing sustainable aviation fuel. Alder technologies along with Honeywell’s Ecofining process will have the ability to produce a carbon-negative fuel at spec with today’s jet fuel. This fuel will be a 100 per cent drop-in replacement for petroleum jet fuel. As a part of the agreement United will be purchasing 1.5 billion gallons of SAF from Alder. This purchase agreement is one and half times the size of the known purchase commitments of all global airlines combined, making this the largest publicly announced SAF agreement in aviation history.