Flutr Motors is working on the two-seat Flutr VTOL but believes all-electric is not the best way to go, and so its propulsion system will run on bio-diesel fuel.
The Flutr DTEH (Diesel Turbine Electric Hybrid) features ducted rotors.
Flutr started in 2016 and now has a flying prototype, which the company said is being "iterated toward the goal of stable transition flight, certification, pre-production, sales, and deployment." Projected range is 125 miles, and its speed will be 155 mph.