The use of land transportation, primarily cars, is increasing annually. The energy required will increase along with the number of vehicles. Thus far, car manufacturers are required to improve car designs and propose fuel-efficient and environmentally friendly cars. The energy-efficient car competition, namely, Kontes Mobil Hemat Energi Indonesia, is organised for mechanical engineering students to contribute directly to research related to energy-efficient cars in Indonesia. One of the ways to save fuel is to reduce the aerodynamic force drag on the vehicle. This study aims to optimize the prototype vehicle airfoil design in producing the smallest possible coefficient of drag (Cd) and lift (Cl). A Taguchi design of experimental (DoE) is applied to set the 9 designs for this study, with three different values considered for each design parameters: Defiant Canard BL110, Clark YM15, Gottingen 256 for side airfoil shapes and Gottingen 410, Gottingen 460, and Boeing 737 Root for top airfoil shapes. This aerodynamic analysis uses the ANSYS 2020 R1 software, which is carried out at a speed of 30 km/h. Then the Cd and Cl values obtained will be analyzed. The results obtained for the optimal design of the Cd with variations in the side airfoil design Defiant Canard BL110 and top airfoil is Gottingen 410 with a Cd value of 0,1119. As for the optimal design of the Cl with variations in the side airfoil design Gottingen 256 and top airfoil is Gottingen 460 with a Cl value of 0,0250.