In modern aviation, aircraft efficiency is not measured solely by the power of engines or the precision of navigation systems. The real secret lies in something less visible yet profoundly influential: the materials from which aircraft structures are made. Here, materials engineering emerges as a fundamental pillar that has redefined aircraft design, enabling unprecedented levels of performance, safety, and efficiency. In its early days, the aviation industry relied heavily on traditional metals such as aluminum, valued for its relatively light weight and good corrosion resistance. However, as performance demands increased and the need to reduce fuel consumption and emissions grew, this option was no longer sufficient. Materials engineering began to play a deeper role, developing advanced materials with exceptional mechanical and thermal properties. Among these are composite materials, which combine light weight with high strength. Materials such as carbon fiber reinforced polymers have become the backbone of modern aircraft structures. The relationship between materials engineering and aircraft structures goes far beyond simply choosing the right material. It is a complex process that begins with understanding the atomic behavior of materials, extends to analyzing their properties under various operating conditions, and includes studying how they respond to dynamic and environmental stresses. During flight, an aircraft experiences significant variations in temperature, air pressure, and continuous vibrations, all of which require materials capable of maintaining their integrity and performance. The contribution of materials engineering is not limited to enhancing performance; it also plays a critical role in improving safety. Modern materials are designed to exhibit gradual failure behavior, allowing engineers to detect defects before they evolve into catastrophic failures. In addition, non-destructive testing (NDT) techniques—built on a deep understanding of material properties—have become an essential part of aircraft structural maintenance. Moreover, materials engineering has significantly contributed to environmental sustainability in aviation. Lighter materials lead to lower fuel consumption, which in turn reduces carbon emissions. Efforts are also underway to develop recyclable materials or those with minimal environmental impact, opening new pathways toward more sustainable aviation. With the continuous advancement of manufacturing technologies such as 3D printing, materials engineering has become increasingly integrated with structural design. It is now possible to manufacture complex components using materials specifically tailored to meet precise requirements. This integration allows for the creation of structures that are lighter, stronger, and more efficient than ever before.