That's no big deal. After all, they make (or made) ball bearings by dropping molten metal off a tall tower. The plane dropped for a much longer time, giving plenty of time for a "metal fog" to form droplets that solidified as spheres.
There's still the problem of how such a fog might form, but that, too, might be explained away. Titanium has very high melting/boiling point (3034/5948 degF), but if it came into contact with burning aluminum (~5700 degF).
The missing link would be an ignition source for the aluminum, though it's possible that a high-voltage electrical spark onto a jagged edge might provide the necessary heat.