In the grand scheme of global CO2 emissions, the aviation sector is a minor contributor, with an approximate 2% share. Within the transportation sector, aviation is also dwarfed by its passenger vehicle and heavy-duty vehicle counterparts. However, the outlook in the coming decades is drastically different. The aviation sector's expected growth is exacerbating the emissions problem, as the total number of airline passengers is expected to more than double by 2050. As a result, jet fuel demand is expected to rise to 1.8 trillion liters in 2050 and result in a nearly fourfold increase in CO2 emissions at a projected 2.1 GT in 2050 unless the industry makes serious efforts to reduce its carbon footprint. Several airlines have announced projects and initiatives in the past year, each taking a different strategy to address the near- and long-term potentials of the various solutions.