In this chapter we shall present the results obtained by the experimental and numerical campaign, apt to validate the proposed control and estimation methods presented in Chap. 4. In particular, we recall that we designed:two hierarchical controllers for the outputs; three dynamic feedback linearizing controllers for the output, and; a nonlinear observer based on IMU and three encoders readings;a nonlinear observer based on the IMU readings only, valid for the reduced model. The first hierarchical controller has been mainly tested experimentally and has been successfully employed to perform the landing and takeoff on/from a sloped surface (see Chap. 6). The successive dynamic feedback linearizing controllers designed for the tracking problem, and the nonlinear observers have been tested together by a careful simulation campaign. We performed a thorough simulation analysis in non ideal conditions as well, like with noisy measurements, parameter uncertainties and so on. With this we assessed the robustness of the proposed methods and the corresponding limits, beyond which the system turns out to be unstable. Due to the limited available time, the implementation and the experimental test of those controllers and observers are left as future work. We also remark the fact that the dynamic feedback linearizing controller for has been tested by simulations only for the reduced model. This because the dynamic feedback linearizability of the system w.r.t. for the generic model, and the corresponding tracking controller have been found only very recently. Thus, we had not the time to run exhaustive simulations to test it. This and the corresponding experimental validation is also left as future work.