US: Aerospace giant Boeing is turning science-fiction into reality. The company recently patented a drone that can turn into a submarine. Basically, the proposed vehicle is adaptable for both flight and water travel. To optimise its hydrodynamic properties, the drone would shed its wings and propellers using explosive bolts and water soluble glue. A set of water-borne propellers and control surfaces would appear in their place. Both air and water versions of the vehicle are supposed to use the same engine, though the company hasn’t specified which one.