The SolarShip is a helium-filled airplane that resembles a balloon, and is powered by electrically driven propellers whose power is collected from the Sun. This sort of aircraft doesn’t fit into any existing category, it is its own category. A picture may help:
Essentially it’s a blimp/balloon, filled with helium, and it has wings and a propeller. The wing surface has solar panels, which charge a battery pack.
The SolarShip is envisioned for use in remote areas like Africa. The tag-line is “no roads no fuel” which describes some parts of Africa.
The SolarShip gets its lift both from the helium, and aerodynamics. The wing design allows very short take-off and landing (VSTOL) operation.
Solar Ship is a buoyantly assisted aircraft, possible through a confluence of modern developments. Advanced aerodynamics, synthetic textile laminates, smart electronics, lightweight batteries, and high-efficiency photovoltaics are the enabling technologies that now allow us to realize the vision of a practical solar aircraft.
By combining hybrid aerospace design with advanced propulsion, Solar Ship carries a truck’s payload, with greater flexibility than an airplane, with unrivaled efficiency. The design also scales well, with a payload that grows cubically as its size increases.
http://www.treehugger.com/aviation/solarship-solar-powered-helium-filled-cargo-plane-floats.html