This paper applies a newly developed optimal dynamic output feedback control method to control the angle of attack α and pitch angle θ (for longitudinal control), and the angle of sideslip β and roll angle φ (for lateral-directional control), so that pilot can maneuver and control the airplane to the desired flight attitude precisely. The control design model is based on the linearized aircraft model. The unmodeled high frequency dynamics are ignored in this model. Singular perturbation method is used to analyze the effects of the unmodeled high frequency dynamics of the proposed controller. It is shown that the unmodeled dynamics affect the poles of the closed-loop system in the order of O(ε) only. The computer simulations verify the desired performance of the proposed scheme.