Kevlar and glass fiber composites have distinguished mechanical properties such as specific strength and stiffness, resistance to impact loading, and tailoring the overall properties to meet the needs of a specific application. Enhancing their mechanical properties via incorporation of carbon nanotubes (CNTs) into their polymer matrices and proper characterization are very important for automotive and aerospace applications, which is the main objective of this study. This article presents an experimental study on manufacturing and mechanical characterization of six different materials. The tested materials include: CNT-nanocomposites, Kevlar fiber reinforce epoxy (KFRE) and glass fiber reinforced epoxy (GFRE) composites modified with CNTs. The CNTs were ultrasonically dispersed into the epoxy resin at 30% sonication amplitude (225 W) for 30 min to avoid their damage. The results were compared with the control materials (without CNTs). The mechanical tests are drop weight impact, tension, and in-plane shear. All the tests were performed according to ASTMs using computerized testing machines at room temperature. Results from the experimental study showed that the incorporation of the CNTs into the epoxy resin improves their tensile and shear strengths by 11% and 22.2%, respectively. In addition, the tensile and shear moduli of the CNT-nanocomposite were improved respectively by 68.7% and 29%. The absorbed energy and maximum contact force of the CNT-nanocomposite were improved by 11.4% and 9.5%, respectively. The tensile strength of the GFRE/CNT and KFRE/CNT composites showed improvements of 15.3% and 19.6%, respectively. The improvements in the tensile and shear moduli of GFRE/CNT and KFRE/CNT composites are in the range of 15–20%. The CNTs have marginal effects on the impact properties of the modified composite laminates. The tensile properties of the Kevlar composite systems (with and without CNTs) are higher than those of the glass composite systems and vice versa for the shear moduli and the absorbed energies.