An aerial vehicle comprises an elongate envelope within which are at least one first compartment for holding a lighter than air gas and at least one second compartment for holding atmospheric air and said at least one second compartment having an inlet and an outlet and at least one pair of wings extending laterally from the envelope; said wings being planar units with a leading and trailing edge, the width of the wings from their leading edges to their trailing edges being substantially less than the length of the envelope with airfoil portions fitted between the leading and trailing edges of the wing: the top and bottom of the wings are mirror images of one another; in which forward motion of the vehicle is obtainable without trust through alternate diving and climbing motion.