Innovation is always advancing and does not stop at aviation. Recently, the first research reports were published about which commercial aircraft will be made more CO² neutral or even emission-free in the future. (Editor's note: Airbus, for example, has published https://fly.airbus.com/3lN9M9x, opens an external URL in a new window in December 2021 on hydrogen storing solutions for zero-emission flights, as one of the biggest challenges in this propulsion sector).
It's not a secret: hydrogen can be the environmentally sustainable energy carrier of future airliners. Hydrogen engines are nothing new in principle, and hydrogen has long been indispensable in space travel.
As an airline pilot, I welcome every form of innovation and can very well imagine that one day I will no longer fly a classic "kerosene burner". In any case, I would also like to see a reduction in the complexity of the aircraft, because new technologies often bring in an increased amount of information and its processing is not always efficient or stringent.
Of course, safety will always be a top priority in aviation, and the major aircraft manufacturers face a major challenge here when it comes to hydrogen. Whether running electric motors via a fuel cell or feeding hydrogen directly into the engine, pressurized, cryogenic hydrogen tanks require a new aircraft design.
Normally, the largest amount of kerosene is in the wings and thus near the center of gravity, only there it is not pressurized. More likely here is the use of pressurized tanks in the fuselage. However, this results in a loss of cargo volume, and the consumption causes a shifting center of gravity during a flight, which must be compensated for and has further aerodynamic consequences.
Another aspect is the economics around infrastructure. An aircraft should be economical, and it can do that best when it is in operation. That's why all airlines, especially the so-called low-cost airlines, try to reduce aircraft downtime to an absolute minimum.
If this downtime was now to be extended by refueling the aircraft for too long, the manufacturers would not be able to hope for a great response from the airlines.
It quickly becomes clear that there are many points to consider here.
If something is safe and works, it is very much welcome for me as a pilot. Efficiency is one of the most important aspects in flight operations, after safety, and in my opinion this will soon be exhausted in conventional engine and turbine construction. In the short term, the increased use of synthetic fuels (SAF) will help make aviation more sustainable. In the long term, I estimate that research and development will always be able to turn new ideas and concepts into reality.