Aging of polymer composites is a wide-spread problem, which causes deterioration of mechanical properties, shorter design service life of structures and their potential early destruction. The work presents the results of experimental researches, within which the impact of elevated temperatures on mechanical properties of airborne constructional fiberglass were investigated. Research results were obtained, which describe the impact of the preliminary temperature aging (in different modes) on mechanical properties, behavior and execution of different composite destruction mechanisms during interlaminar shear testing. Experimental data were obtained, which describe the temperature impact on the mechanical behavior of constructional fiberglass samples at interlaminar shear. Regularities of fiberglass properties changing after temperature aging at interlaminar shear were analyzed, based on the joint use of testing systems and an acoustic emission (AE) signals recording system. Dependences of AE signal energy parameters on the time, combined with diagrams of fiberglass samples loading were obtained. Results of the distribution of specific frequency bands obtained after the destruction of samples with different preliminary aging modes, are graphically represented.