Hybrid Air Vehicles (HAV) Limited is a British limited company and a British manufacturer of hybrid airships, though none have been built since the crash of its last demonstrator in Nov 2017. These aircraft use both aerodynamics and lighter-than-air (LTA) technology to generate lift, potentially allowing the vehicle to stay aloft for several weeks.
The HAV-3 scale demonstrator
A hybrid airship is a powered aircraft that obtains some of its lift as a lighter-than-air (LTA) airship and some from aerodynamic lift as a heavier-than-air aerodyne.
The HAV 304 dynastat, seen bow-on
Solar Ship, a solar-electric and helium filled flying wing airplane