A direct adaptive interval type-2 fuzzy neural<br>network (IT2-FNN) controller is designed for the first time<br>in hypersonic flight control. The generic hypersonic flight<br>vehicle is a multi-input multi-output system whose longitudinal<br>model is high-order, highly nonlinear, tight coupling<br>and most of all includes big uncertainties. Interval type-2<br>fuzzy sets with Gaussian membership functions are used in<br>antecedent and consequent parts of fuzzy rules. The IT2-<br>
