Alaska Air Group has delivered to ZeroAvia (Hollister Municipal) the first DHC-8-Q400 to be used as a testbed and certification platform for hydrogen propulsion.

N441QX (msn 4348) was retired by Horizon Air (QX, Seattle Tacoma International) in August 2021 and has since been parked at Sault Sainte Marie, ON, Portland International, Victorville, and Centralia Huron. It was ferried back to Everett on March 13, 2023, and officially presented as ZeroAvia's testbed aircraft on May 1, 2023. It remains owned by Horizon Air and sports a hybrid ZeroAvia/Alaska Airlines livery.

Alaska Air Group was an early investor in ZeroAvia, backing the hydrogen-propulsion start-up in 2021. The holding secured options to acquire up to 50 conversion kits following certification of the new type of propulsion. The first hydrogen-powered engines are expected to enter into service in 2027, with the first test flight scheduled for 2024.

The ZA2000 hydrogen propulsion system for Q400-gauge aircraft marks progress from the already more advanced ZA600 system, which ZeroAvia is trialling on its two Do228-200s. The first flight took place in January 2023.