A protective skin (143a, 143b) for an aircraft is disclosed. The protective skin (143a, 143b) forms the leading edges of wing members, horizontal stabilizers, and vertical fins. A portion of the skin material (143a, 143b) is removed in a selected pattern (155a, 157a, 159a, 161a, 155b, 157b, 159b, 161b) from the interior surface of the skin (143a, 143b). In the preferred embodiment, the interior surface of the skin is chemically etched and / or mechanically milled in oval and rectangular patterns so as to create crumple zones (155a, 157a, 159a, 161a, 155b, 157b, 159b, 161b) and generate progressive failure of the metal. This allows the leading edge to absorb the impact energy from a collision with a bird or other object, and prevent the bird or other object from penetrating through the leading edge into the substructure.