Without the Carbon Dioxide?

Cranfield University (like a number of other institutions) has been exploring methods of achieving 'sustainable air travel' (https://www.theguardian.com/environment/2021/aug/14/they-said-we-were-eccentrics-the-uk-team-developing-clean-aviation-fuel). The main problem of the current paraffin-fuelled air travel, is its massive production of 'greenhouse gas' emissions. One candidate they have considered involves replacing paraffin with pure hydrogen as a fuel. Having said that, there might be a debate about whether 'blue hydrogen', obtained from natural gas, can be used. Producing 'blue hydrogen' does generale carbon dioxide and methane that can escape into the atmosphere. When pure hydrogen is burned, it generates only water. The Cranfield team have demonstrated (in engineering set-ups, rather than aircraft) that hydrogen can be successfully ignited. It can also be safely combusted, at high temperatures and pressures, without producing carbon emissions or concerning amounts of nitrous oxides. Although the results are promising, we are a long way from 'sustainable air travel' for anything but the smallest of aircraft. Emissions need to be cut now!