The Solar Impulse solar-powered aircraft is undergoing test flights in preparation for its 2012 flight across the world.
Solar Impluse aims to become the first solar powered plane to circumnavigate the world without conventional fuel.
It is hoped that the plane will be able to take off and fly, day or night, with the power stored in its batteries.
A large wing surface area is required to accommodate the solar cells needed to generate enough power for its four electric motors.
The plane, with the wingspan of an Airbus A340, has a lightweight architecture to save energy to sustain after-sunset flight.
The project is being supported by the German Aerospace Centre (DLR) that recently carried out ground vibration tests on prototypes in Zurich.