ZeroAvia and KLM are planning a hydrogen demonstration flight by 2026 with commercial flights likely to commence soon after, Rethink believes. Hydrogen’s pace in aviation has ostensibly slowed down in recent years or was never on track in the first place, as a few companies had claimed to be eying flights in Denmark by 2025. One related company, Universal Hydrogen, went bust a few weeks ago due to a lack of funding. Aside from technological hurdles like getting a new powertrain certified to lay the path toward new airframe designs, hydrogen’s biggest problem has turned out to be safety risks like flammability, as compared to Jet-A1. Nonetheless, Airbus is still committed to introducing hydrogen-powered aircraft by 2035, and plans to…