A dual-state propulsion aircraft includes an aircraft fuselage; and at least one dual-state propulsion system, including a fixed nacelle, a rotatable nacelle optionally including a front curved section and rear straight section, mechanical nacelle rotation stops, mechanical shaft rotation stops, a motor, and a thruster with pivotable blades; such that the at least one dual-state propulsion system is rotatable to a first system position configured for horizontal flight and to a second system position configured for vertical flight.