Abstract: A sailing craft that can transform from wind propulsion mode to flying mode, comprises a body and two sails or wings each pivotally connected to a common boom which is supported by a spar pivotally connected to the body. The dihedral angle between the wings can be varied by a system of adjustable stays between the masts and the upper and lower ends of the spar. In sailing mode, either wing can be tilted essentially upright and swung relative to the axis of the body to derive propulsion from the apparent wind whilst the other is essentially horizontal to develop counter balancing moments. In flying mode, both sails can be tilted essentially horizontal to derive lift from the apparent wind.