Which characteristic is essential for plywood used in aircraft construction?

Plywood used in aircraft construction must possess significant water resistance. This characteristic is vital because aircraft are exposed to various environmental conditions, including moisture from rain, humidity, and potential condensation that can occur during flights. If the plywood absorbs water, it can lead to issues such as delamination, weakening of the structure, and ultimately failure of the aircraft components.

Water-resistant plywood helps maintain the integrity and longevity of the aircraft materials, ensuring safety and performance during operation. While other characteristics such as low weight and high tensile strength are also important for aircraft materials, they do not address the critical need to withstand moisture. High elasticity can be useful in different contexts but is not a primary concern when considering the use of plywood in aircraft construction.