needs to be certified. we need to provide the hydrogen infrastructure to the, uh, to the aircraft. zeroavia has a plan for that. in its vision, hydrogen would be produced on site at airports using renewable energy before being processed and transported out to the plane. but what about the cost of all this? at the moment, liquid hydrogen is significantly more expensive than conventionaljet fuel, but backers of hydrogen planes believe it will eventually become cheaper than traditional flight. zeroavia isn't the only company racing to reimagine air travel, though. aerospace giants like airbus and boeing are also developing hydrogen planes. but there are still questions over how sustainable they'll actually be. we're going to be using some fairly exotic materials that are very energy intensive to arrive at. what energy are you using to build the fuel cell? what materials are you using? how much energy are we sinking