The attitude control problem and the guidance problem are solved in 3D for a buoyancy driven airship actuated by the combined effects of an internal air bladder which modulates the airship's net weight and of two moving masses which modulate its center of mass. Nonlinear control loops are derived through maximal feedback linearization with internal stability for both dynamics in the longitudinal plane and inthe lateral plane. Based on a singular perturbation approach, the superposition of these two control actions is shown to achieve the control of the dynamics in 3D space.