Lesson OneText课文：The Classification of Aircraft 飞行器的分类Although all airplanes are aircraft, not all aircraft are airplanes. An aircraft is any structure 虽说所有的飞机都是飞行器，但不是所有的飞行器都是飞机。飞行器是指通过空气航that is Intended for navigation through the air and that is supported either by its own buoyancy or 行，由其自身的浮力或者依靠作用在其表面的空气动力支撑的一种结构。by the dynamic action of the air against its surfaces. A brief look at the various kinds of aircraft is
