When carbon fiber plastics are modified with carbon nanoparticles, it is particularly important to evaluate the effectiveness of such modification in terms of increasing the mechanical properties compared to the analog. Of particular interest is the comparison of the fatigue strength characteristics of modified carbon fiber plastics and analogs, since it is these characteristics that determine the performance qualities of materials. The strength properties of VKU-18tr carbon nanocomposite and its analog, KMU-4-2m-3692 carbon fiber, are considered. It is noted that there is no detailed comparison of the key fatigue strength characteristics of these plastics in open publications. In order to conduct such a comparison, three methods and three types of comparison were chosen: comparison of the fatigue life of materials with a symmetrical loading cycle; comparison of the fatigue life of materials until a certain level of degradation of residual strength is reached; comparison of the fatigue life of materials until a certain level of degradation of stiffness is reached. Despite the certain conditionality of the comparisons, a significant advantage of the main characteristics of the fatigue strength of the VKU-18tr carbon nanocomposite compared to its analog, KMU-4-2m-3692 carbon fiber, is noted. The superiority quotas reach values of 125–536%. It is obvious that such an advantage can be an extremely important property in the design of particularly critical power elements of structures (for example, composite wing panels of aircrafts).