This work presents the automatic control of airplane in longitudinal and lateral-directional planes, during landing, by using the H-inf control and the airplane's linearized dynamics; the H-inf control technique assures robust stability with respect to different disturbances and noise type signals. Both the longitudinal plane and the lateral-directional one are treated; three automatic landing subsystems (ALSs) are obtained: the first two control airplane's motion in longitudinal plane, while the third one is employed for the airplane's control in lateral-directional plane. Before the landing's two main stages in longitudinal plane, the pilot must cancel the airplane's lateral deviation with respect to the runway in lateral plane. The three subsystems have been designed separately and put together to form a single ALS. The complete ALS has been software implemented, tested, and validated through numerical simulations; promising results have been obtained.