Airborne wind energy conversion system with a propeller (4102) and a ground generator (4107), comprising a cross wind flying wing (4101), in which mechanical energy is transferred from the wing to the ground generator using an endless belt (4105). Another airborne wind energy conversion system, comprising a rotor, formed by freely moving wings, transferring its mechanical power to a ground based generator via a belt. The system can utilize a ribbon, connecting the wings. The belt can move continuously or reciprocally. The rotor can be axial flow, cross flow, diagonal flow or 3D flow. Related AWECS raising and landing methods are disclosed.