Airlines rely on advancements from aircraft and engine manufacturers to achieve true zero-carbon emissions. The current net-zero carbon policy, driven by increasing the use of Sustainable Aviation Fuel (SAF), has significant drawbacks, including continued CO2 emissions and contrail formation, both of which contribute to global warming. As a result, numerous hydrogen-powered aircraft projects have been launched. This discussion will cover these initiatives and review the engine technology options for hydrogen, including both fuel-cell and combustion solutions, which have the potential to deliver a true zero-carbon future.