For novel passenger aircraft with pronounced aeroelastic effects, primary flight and aeroelastic control should be addressed simultaneously, and, due to their inherent coupling with the airframe, flight control development should begin early in the aircraft's design process. To facilitate such a control co-design, early stage, cost-effective hardware tests are required, to validate and mature the developed controllers. Wind tunnel testing provides hardware-in-the-loop capabilities to test primary flight and aeroelastic control. However, it poses constraints on model size and realizable maneuvers. To address these challenges, this paper proposes a simulation-enhanced wind tunnel testing approach, in which the physical model is augmented by an aircraft simulation. The setup is tailored to aeroelastic applications by testing only a subcomponent of the aircraft, typically the wing, inside the wind tunnel, while representing the remaining aircraft dynamics in simulation. This allows the component to be scaled for best representation of the aeroelastic behavior. This paper presents the overall architecture of this setup, including the interfaces between experiment and simulation, and the implementation of the control functions to be validated. The capabilities of the approach are demonstrated by the implementation and experimental validation of an integrated control design combining primary flight and aeroelastic control. A roll rate-command attitude-hold controller is coupled with gust load alleviation. The validation allows to assess the performance of the control law and the interaction between primary flight and aeroelastic control. The results demonstrates the merit of such a simulation-enhanced wind tunnel test in controller development, allowing for a cost-effective wider range of testing scenarios.