He system identification methods make an important part of the flight test data analysis. Due to these methods accurate aircraft parameter estimations can be obtained, which meet the requirements of numerous applications, such as simulators and flight control systems design, aircraft modernization, etc. The aircraft parameter identification, when applied to the processing of the actual flight test data, faces the following principal problems: inevitable differences between a physical object and the adopted mathematical models; an essential incorrectness of the identification problem, since it belongs to the class of the inverted problems of dynamics. The presented techniques are intended to overcome those difficulties, using a system approach. That means that the identification problem is treated as an integral multistage system, designed on certain basic principles. These principles are the following: every stage includes a verification procedure; a decomposition of the general problem into minor subproblems; a systematic search for all the useful information in the relevant disciplines; an important role of a human operator. The article presents an algorithmic and methodological support for monitoring of the correctness of the airborne measurements and estimation of the aerodynamic nonlinearities for identification of the aerodynamic coefficients of the aircraft according to flights test. The paper also presents numerous examples of the practical applications of the considered methods and algorithms in the process of the parameters identification of the mathematical models of certain modern aircraft, using the flight test data. The authors believe that the choice of those examples would be helpful for understanding of the typical problems of the aircraft parameter identification.