[slapfrog]

This video shows an F-4 Phantom being slammed into a concrete wall using a rocket sled: https://www.youtube.com/watch?v=U4wDqSnBJ-k

At about 2 minutes in they show the aftermath. The plane is just gone, while the wall is a bit discolored...

[worik]

Unconvinced.

That concrete block was not ridged. It moved when the plane hit it.

So the strongest aspect of concrete, compression, was tested. But the weakest, flexion, was untested.

What fun though.

[slapfrog]

To test it as you suggest, you'd have to build the full containment building, which are built as domes. That dome structure should lend itself to exploiting concrete's compressive strength and minimize tensile forces. They are also specifically reinforced to increase their tensile strength, since they are primarily designed to contain explosions from within. I have little doubt that one of those domes could shrug off a Phantom crashing into them.

More generally, in order to be successful a traditional armor piercing projectile needs two traits in particular: it needs to be harder than the target, and the projectile needs to be robust enough to not disintegrate on impact. Airplanes are neither of these; they're built out of soft aluminum and are built light to maximize payload, not to be robust. Consequently I would not expect an airplane striking a reinforced concrete building to ever behave as an armor penetrating projectile would.

The part that I'm a bit skeptical of is the suggestion that shrugging off a Phantom is equivalent to shrugging off a 747, which is more than an order of magnitude heavier. Throwing an airplane at a concrete building is like throwing a wet ball of modeling clay at a glass window. Likely to splat, like that phantom did, but if your ball of clay is big enough it might go through. A large enough plane might even knock the building off its foundation, rather than penetrate the concrete.