The future of aviation fuel may turn less on how it is produced than on how its raw materials are collected, according to ReFeed CEO Lee Chung-ho. The company is building a business around used cooking oil -- or what Lee calls "liquid gold" -- an increasingly critical feedstock for sustainable aviation fuel, or SAF. With SAF mandates expanding in Europe and set to begin in Korea in 2027, demand for such feedstocks is expected to increase. "The success of the SAF industry depends not on producing