It's not the same thing. In addition to the properties of the materials, there's also the force per area consideration. In the case of a bullet, it's has a small surface area but tremendous force, so it punctures.

In the case of Aluminum v. steel, aluminum can easily puncture steel... if you make it small enough and apply enough force, like an aluminum needle shot from a railgun. In a one to one comparison however, aluminum is far weaker than steel. No aluminum airplane wing is going to go through a steel beam, no matter how fast it's going. It just isn't small enough (too much surface area) and isn't going fast enough (not approaching the speed of light). In the case of a wing, it's also not solid, but a shell. Most of the wing is hollow.

If the airplane above hit that lamp post at high speed it would be obliterated. It would probably knock the lamp post over (because of the strength of concrete) and would probably bend the steel in the post, but it would destroy the wing long before the lamp post broke. The lamp post also isn't solid, and built into a lattice to enhance it's strength, like the beams of a building are.

These both sound dangerous. In any case, what happens?