Ground testing facilities have been used since long in aeronautics and aerospace, as they have been developed for environmental and industrial applications. Nowadays they are still major sources of key data for investigations in all fields of fluid dynamics. This hybrid lecture series (online / on-site) is organized for student and engineers to provide a general understanding of the design, operation and application of ground testing facilities from all speed regimes. Experimental methodology is exposed as well as the interpretation of the data and their extrapolation to real situation. The course includes an on-site presentation of the VKI facilities during a lab visit (for on-site participation only). A question/answer session will be organized for the online participants. The schedule of this session will be communicated later. This Lecture series is based on the long tradition and experience developed at VKI on experimental testing.