The aim of this paper is to study, analyze and model the effects of non-standard atmospheric conditions on aircraft performance and to compare them with the performance of aircraft in a standard atmosphere. The condition of the atmosphere plays a very large role on the flight and performance of the aircraft. Of the individual parameters, we can safely say that the most significant influence is that of temperature on which are directly depended the amounts of others. It is of interest to us to know what performance the aircraft will have in flight, so certain terms have been clarified for the particular flight mode of the aircraft, with many formulas and a description of how to obtain certain information related to the performance of the aircraft. In addition to exposing the non-standard atmosphere, brief descriptions of the types of non-standard atmospheres that have been studied in the past are given in various manuals, or standards, by the United States Department of Defense from which the data are required and collected. In this paper the object of analysis is the aircraft DASH 8-Q400 with the belonging envelope of the aircraft, the range, the endurance, the required runway length, etc., and particular emphasis is given to the creation of a non-standard atmosphere model that allows us to display this data for different types of atmosphere. Finally, an analysis of the effect of wind on runway length under different conditions was made. In this paper, five different types of atmosphere are analyzed and a comparison of the required performance of the considered aircraft versus the standard atmosphere is made. MATLAB was used for data processing, programming and visualization.