Just a few years ago, large unmanned cargo aircraft looked to be decades in the future. But the growth in e-commerce and demand for rapid delivery has encouraged startups to launch development of autonomous freighters, targeting entry into service as early as 2020. California-based Elroy Air and Natilus are close to flying subscale prototypes of their unmanned cargo aircraft while Sabrewing Aircraft, another startup based in the state, hopes to fly its 65%-scale vehicle this fall. And they ...
