The paper describes the development of the methodology of the choice of aircraft fleet’s inspec-tion intervals. This methodology is verified, using the experimental fatigue crack growth data. Meth-odology includes in the economic parameters, such as the inspection costs. Using this method it is possible to find safe- enough and the most cost- effective inspection planning programs. In addition the paper includes testing of the methodology at different design permissive fatigue failure (FF) prob-abilities and their impact on the real probability of FF and the number of inspection intervals for the model with one aircraft and with aircraft fleet.