The aim of this thesis is to anlyse and investigate the stability and control characteristeristics of an airplane. The aerodynamic forces and moments acting on the airplane are calculated based on the geometry and inertial properties of the airplane. The airplane's equations of motion for lateral mode are derived in terms of the aerodynamics forces and moments. Using the calculated aerodynamic forces and moments. Using the calculated aerodynamic forces and moments, the transfer functions of the airplane which gives the relation motion and the control surfaces deflection are derived. The stability of the airplane in the lateral mode are determined using the characteristic equation obtained. To analyse the lateral motion of the airplane, the transfer functions approximation for the spiral, the transfer functions apptoximation for the spiral, rolling and Dutch roll motion are derived. Autopilots for controlling the Rolling and the Dutch roll motions of the airplane are designed using vertical and rate gyros. These autopilots maintain the roll angle of the rolling motion and provide damping for the Dutch roll motion. The prperformance of these autopilots in carrying out the above control functions are compared with the performance of human pilot. The response of the Dutch roll motion to an impulse disturbance is also analyzed.