Hydrogen jets could be cheaper to run than fossil fuel planes from 2035 provided kerosene is taxed adequately, a new study shows. In 2035, running planes on hydrogen could be 8% more expensive than using kerosene. But with a tax on fossil jet fuel and a price on carbon, hydrogen planes could become 2% cheaper to operate than their kerosene counterparts. These pricing measures are key to the deployment of green technologies like hydrogen planes, T&E says.