Which material type is typically used to ensure a smooth transition between two surfaces with different heights?

The use of fairing in aircraft maintenance is crucial for ensuring aerodynamic efficiency and structural integrity. Fairings are specifically designed components that create a smooth transition between surfaces of different heights on an aircraft. This is important not only for maintaining the streamlined shape of the aircraft but also for minimizing drag and enhancing performance during flight.

In terms of their function in aircraft structures, fairings serve to bridge the gap between components, such as between the fuselage and wing, or around landing gear, thus promoting a better airflow over these critical areas. This kind of transition is essential for maintaining the aircraft's low observable characteristics, as irregular surfaces can disrupt airflow and increase visibility to radar.

While sealant, composite materials, and fillers have their specific applications within aircraft maintenance and construction, they do not specifically serve the function of providing a smooth aerodynamic transition between varying surface heights as effectively as fairing does. Sealants are typically used for sealing joints and preventing leaks, composites are materials used for constructing elements of the aircraft, and fillers are generally used to fill gaps or imperfections in surfaces rather than to create smooth transitions. Thus, fairing stands out as the most appropriate choice for this purpose.