The present project aims to the analyses and model the autonavigation process. Putting mathematical model for aeroplane autonavigation requires an understanding to the aeroplane mobility in atmosphere, and its relationship with the control surfaces in the aeroplane. After the accomplishment of the analysis and modeling, an auto-navigation control system was designed by using the devloped model. The developed control system is oriented to be a navigator to auto-control the aeroplane. In addition to the establishment of navigation programs, a graphical user interface was developed to display the state of the aeroplane. Hence the observer would have a chance to monitor the events which the aeroplane may undergo during its flight. In order to test the accuracy of the navigator_s performance, a simulation model was developed and impelemented with the aid of the actual input data the simulator was utilized to investigate the navigator_s response. The encourageing results of the simulator paved the way to start improving the conducted work. An adaptive method had been suggested, so that the response of the aeroplane become dynamic instead of the static response which is already present. The dynamic response was curried out by two automatic methods which both depend on the amount of deviation between the actual airplane response and the planned response. The results of the dynamic response were more accebtable. The next accomplished step was modeling and simulating the external effects that would influence the performance of the aeroplane in the atmosphere. By studying the wind effect on the aeroplane_s performance during its flight, and analyzing the aerodynamic forces that would deviate the aeroplane from the planned routes, an algorithm was added to the simulator to determine the actual speed of the aeroplane after considering the wind speed and the wind force on the aeroplane_s head. The efficiency of the aeroplane_s engine has been modeled and added to the simulator taking into account the type of the used fuel. The last effective factor included in the simulation is the effect of the elevation and the amount of the oxygen concentration on the performance efficiency of the engine, which in turn will affect the aeroplane fly efficiency. This was curried out by proposing a simple mathematical model by which the simulator could adopt its performance at various elevations. In general, the simulation results were encouraging, as described by the behavior test results under different conditions related to atmosphere and engine efficiency at various elevations. In addition, some unpredicted and interesting situations were investigated (such as the sudden motion of the aileron or change in its directions). The test indicates that the promoted model and the proposed methods are quite efficient.