Ignorance never stops the imagination.

1. Wings are indeed box beams, formed by the front and rear spars and by the upper and lower main wing skins (stiffened by stringers). The leading and trailing edges are primarily aerodynamic, not structural surfaces. The wing sustains a bending and shear force equal to the weight of the entire airplane, as well as reacting against engine thrust levels and supporting point engine loads (bending and torsion).

2. The wing is not made of tempered steel. It is made from aluminum alloy (all Boeing airliners except the 787 and 777X).

3. The twin towers collisions were messy. The aircraft was significantly diced up, despite severing some structural columns. Ice is weaker than steel, but it didn't stop an iceberg from fatally gashing the RMS Titanic. Water is weaker than any structural material, but it has no problem destroying bridges and dams if there is enough momentum involved.

4. Oh, yeah. The signpost. That happened in a low-speed surface motion, not at 400-500 mph flight velocity. Notice that the post stopped penetrating when it reached the forward spar.

Ignorance never stops the imagination.

1. Wings are indeed box beams, formed by the front and rear spars and by the upper and lower main wing skins (stiffened by stringers). The leading and trailing edges are primarily aerodynamic, not structural surfaces. The wing sustains a bending and shear force equal to the weight of the entire airplane, as well as reacting against engine thrust levels and supporting point engine loads (bending and torsion).

2. The wing is not made of tempered steel. It is made from aluminum alloy (all Boeing airliners except the 787 and 777X).

3. The twin towers collisions were messy. The aircraft was significantly diced up, despite severing some structural columns. Ice is weaker than steel, but it didn't stop an iceberg from fatally gashing the RMS Titanic. Water is weaker than any structural material, but it has no problem destroying bridges and dams if there is enough momentum involved.