The subject of research in the paper is the process of forming a criterion base to evaluate the effectiveness of carrying out modification changes in a transport category aircraft. The goal is to develop supporting criteria for making decisions regarding the expediency of modification changes, namely, during design, during production, and at the stage of its operation, at each stage of the life cycle of a new transport category aircraft. The complexity of the task lies in the need to develop a model for evaluation of the consequences of changing the aircraft for each stage separately, which would collectively determine the integral effectiveness of its modification. To evaluate the efficiency of basic aircrafts in operation, there are a number of economic indicators of their efficiency, in particular, the cost of an aircraft hour and the transportation of one ton of cargo per one kilometer, which are only partially taken into account when analyzing the efficiency of aircraft modifications, although in the case of aircraft transport category, specific cost criteria for the entire life cycle both for the base aircraft and for its modification is required. For their development, a method of estimating the cost of the entire life cycle of the aircraft is proposed, as well as a method of dividing modification changes according to the parameters of the upper level (PMD), which is used at the stage of designing the devices, and the lower level (PPO) for the operational stage. On the basis of and taking into account the specifics of the specified methods, indicators of additional labor costs that arise during the implementation of modification changes in the conditions of production and at the stage of aircraft operation have been developed. The proposed criteria take into account indicators of the transport efficiency of heavy aircraft modifications and the integral efficiency of the modification, taking into account the costs at all the main stages of the life cycle of the modification. The scientific novelty of the obtained results is as follows: the supporting criteria for the adoption of decisions regarding the expediency of modification changes at each stage of the life cycle of a new transport category aircraft are proposed, i.e. during design, under the conditions of production and at the stage of its operation. Such criteria will ensure the integral efficiency of the transport aircraft modification.