Growth in commercial air travel is unrelenting and so is its carbon footprint - worrying airlines, passengers, and policy makers alike. Yet, air travel is the hardest to abate sector. Heavy batteries and decades long development cycles mean air travel won't be electrified any time soon. This is where SAF steps in. What is it? Where is it produced and what is the demand and policy support for it? And can it meet the needs of the industry? Our guest is Steve Mawer, Chairman of Calumet and its Montana Renewables subsidiary- a key producer of renewable fuels in North America.