The performance of any flight control system strictly depends on the feedback control scheme. In this article, two redundant controllers that could be implemented without much difficulty are proposed to boost and improve the capabilities of the popular feedback linearization controller. The first one is built upon the model-free control theory while the second one is based on the sliding mode framework. Herein, the model-free control principle is used to deal with the unknown part of the plant only (i.e. unmodeled dynamics, disturbances, etc.) in addition to the feedback linearization controller that is used instead of the proportional–integral–derivative structure. Unlike the existing sliding mode techniques, the designed one uses an input-dependent sliding surface. An in-depth discussion is highlighted with detailed evaluation in terms of performance, consumed energy, and robustness by considering several scenarios and using several metrics. The numerical simulations have shown satisfactory results considering multi-input multi-output system model through an application to a small quadrotor. The effectiveness of this approach is validated by experimentation.