In this paper, a special class of square multi-input multi-output (MIMO) non-linear non-minimum phase systems is considered whereby the internal dynamics does not depend explicitly on the inputs. For such systems, a new output tracking control aproach is proposed and applied to a planar vertical takeoff and landing (PVTOL) aircraft. This control approach first generates input-output linearization of the original non-linear system. Then the internal dynamics is rewritten by separating its linear part from its non-linear part. Finally, a non-linear auxiliary input is introduced to stabilize the overall closed-loop system by a Lyapunov-based technique and a minimum-norm strategy. The effectiveness and excellent performance of the resulting non-linear state feedback controller are demonstrated by using the simulation results.