CNN  —  Spurred by increasing global demand for air travel, aviation emissions have been rising faster than those from rail, road, or shipping in recent decades. Solutions to invert the trend are slow-dripping: Sustainable Aviation Fuel, which can cut emissions on a flight by 80% when produced and used correctly, could represent two thirds of the reduction in emissions needed for aviation to reach its net-zero goal by 2050. But, it’s in short supply and in the best case scenario, SAF will have