Ammonia Airways?

It seems generally agreed that ammonia is, currently, the only viable 'clean fuel' alternative to kerosene for long haul aviation. Burning kerosene emits tonnes of carbon dioxide, high into the atmosphere. Powering jet engines with hydrogen from ammonia, would produce water droplets with a much lesser impact on climate change (there would still be contrails). The launch of an unnamed UK company was announced (conveniently just before Cop26) to build, by 2030, light weight reactors that could be fitted to existing aircraft. These reactors would extract hydrogen from liquid ammonia, replacing the kerosene, in the plane's fuel tanks (https://www.theguardian.com/environment/2021/nov/05/british-firm-to-unveil-technology-for-zero-carbon-emission-flights-at-cop26). The ammonia fuel would, however, be much more costly than kerosene, increasing the cost of air travel. It also remains to be seen whether the suggested technofix is largely designed to keep current aircraft designs in place, until they can be 'converted' (if this ever happens?). At the present time, the announcement seems to be simply 'pie in the sky'?