High Altitude Platform Stations (HAPS) operating in the stratosphere are being developed for various applications, such as atmospheric observation, telecommunication, and surface surveillance. To fulfill these long-endurance missions at high altitude where meteorological effects are limited, high-aspect-ratio wings are required to enhance aerodynamic efficiency. Generally, such wings are more deformable than low-aspect-ratio wings designed for the same lift and area. However, such flexible wings not only affect the aerodynamic performance in cruise but also increase susceptibility to dynamic aeroelastic issues such as flutter. Therefore, it is essential to design HAPS wings considering aeroelastic effects. In previous research, Kennedy et al. conducted aeroelastic design optimization of high-aspect-ratio wings made of aluminum or composites, in the transonic regime; however, they only addressed static aeroelastic effects, neglecting dynamic aeroelastic phenomena such as flutter. More recently, Jonsson et al. performed design optimization of high-aspect-ratio wings considering the flutter constraint and nonlinear geometric effects. Nevertheless, their study utilized a low-fidelity aerodynamic model based on the potential flow unsteady airfoil theory, which cannot capture viscous and compressibility effects. In this study, we perform aeroelastic design of high-aspect-ratio wings for HAPS in the subsonic regime, considering both static and dynamic aeroelastic effects. We employ a high-fidelity fluid-structure interaction (FSI) analysis based on computational fluid dynamics (CFD) and computational structural dynamics (CSD) for the static aeroelastic sizing process. For dynamic aeroelastic analysis, we utilize a coupling method between CFD and modal-based CSD.