(under subclass 24) Propelled aeronautical machines sustained by their buoyancy relative to the air, having also provision for sustentation by the reaction to downward movement of restricted masses or jets of air or other fluid. The forward propulsion of the machine may also be derived from movement of the same or similar masses or jets of air or other fluid.
(1) Note. For machines having fixed sustaining airfoils as well as means for fluid sustentation, see this class, subclasses 12.1+.
(2) Note. For airplanes, fluid propelled, see this class, subclass 15.
(3) Note. For machines sustained solely by fluid reaction, see this class, subclass 23.
(4) Note. For fluid propulsion and sustentation devices, per se, see this class, subclasses 73 and 74.
