An aerial positioning system consisting of a helium-filled aerostat and three actuated tethers arranged in a tripod is studied. The original concept for the positioning system was introduced as part of a novel large-scale radio telescope. A one-third scale experimental system was developed to compare the dynamic response with the results given by a comprehensive nonlinear dynamics model developed previously. Flight tests were performed in the spring of 2005 that used position feedback and a PID controller to demonstrate the disturbance rejection capabilities of the system. In this paper, the test results are compared to simulation results of the nonlinear model and good agreement was observed. Open-loop frequency response of the experimental system was also compared to that of a linear dynamics model, which also provided a good match. With the dynamics model validated, it was used as a design tool to investigate how certain system parameters, such as the number of tethers, affect performance.