The nose of ZeroAvia’s Q400. The company in 2023 announced a partnering with Alaska Airlines to retrofit the aircraft with ZeroAvia’s powertrain. (GeekWire Photo / Lisa Stiffler) ZeroAvia was flying high. After launching in California in 2017, the clean aviation startup was expanding, establishing an R&D facility in Everett in the shadow of aerospace juggernaut Boeing and running test flights in the United Kingdom. It was raising cash from gover…