ZeroAvia Accelerates Its U.S Hydrogen-Electric Testing ZeroAvia is moving full steam ahead with its testing of hydrogen-electric technologies on 19-seat Dornier DO-228 platforms. The first one has started testing and the company recently received a second DO-228 for the test program. To be clear, this testing is on the United States chapter of ZeroAvia. This company has already been working on hydrogen-electric technology in the UK with the HyFlyer II program. The ZA600 engines with the current timeline are expected to receive FAA certification in 2024.