Two reasons: * There are dozens of aircraft models in use each of which would require significant design changes to run on hydrogen. It’s more practical to des

Two reasons: * There are dozens of aircraft models in use each of which would require significant design changes to run on hydrogen. It’s more practical to design one alternate jet fuel source. * Hydrogen has worse energy density than jet fuel. Energy density is especially important for aircraft. * hydrogen is a lot harder to handle than than jet fuel. It’s more corrosive, more flammable, needs to be kept under pressure or at cryogenic temperatures.