In many practical systems, including aircraft structures, uncertainty exists in terms of the geometry, loads and material parameters. Depending on the nature of uncertainty of the parameters, probability, fuzzy or interval analysis techniques can be used. Quite often the amount of information available on the uncertain parameters is not enough to accurately define the probability distribution functions. Also, the amount of information available for the parameters of the problem may not be enough to describe suitable membership functions required for the fuzzy analysis. The interval analysis requires just the ranges of the uncertain parameters. An interval-based approach is presented for the optimization of aircraft structures under dynamic loads. As a specific application, the effect of uncertainty present in the atmospheric turbulence and other parameters on the dynamic response of the aircraft wing structure is considered. The stresses induced during a gust encounter are considered as the primary behavior constraints. The proposed optimization approach is illustrated through the design of a supersonic airplane wing. The design parameters of the aircraft wing are assumed to be uncertain that are described as interval quantities. Interval analysis is used in the computation of the objective and constraint functions of the problem. An interval-based nonlinear programming technique is developed for the optimum solution of the aircraft wing considered. The present methodology is expected to be more realistic compared to the probabilistic and fuzzy approaches as it does not require nctions or preference information for the uncertain design parameters.