There is also a feeling that some of the newer technologies , such as making fuselages lighter by building them out of carbon-composites instead of aluminium , may not yet be cost-effective for smaller aircraft .
也有一种感觉,一些较新的技术,如用碳合材料取代铝使机身更轻,对较小型飞机而言未必是成本有效的。
Everything else , including the motors , electronics and the lightweight foam that buoys the vehicle , is housed outside the hulls in the fuselages , saving weight .