Plain (pure) aluminum is too soft for most things. Even the skins on airliners are not pure aluminum. They MAY be an alloy base with an aluminum layer on top. It's called Alclad.

Alclad:laminated metal produced in sheets composed of a Duralumin (q.v.) core and outer layers of aluminum.

Duralumin:strong, hard, lightweight alloy of aluminum, widely used in aircraft construction, discovered and patented in 1910 by Alfred Wilm, a German metallurgist; it was originally made only at Düren in Germany. The original composition has been varied for particular applications; it may contain about 3 or 4 percent copper, 1/2 to 1 percent manganese, 1/2 to 1 1/2 percent magnesium