That would be huge news to me if it were true. My understanding of Aluminium is that it is highly reactive but that it quickly forms a passive oxide layer and is hence well protected against oxidation (and is therefore used in marine applications).
If the aircraft/missiles were incinerated after impact then as far as I'm aware they would be the first two aircraft ever to have done so.
A bit of info from wikipedia... (http://en.wikipedia.org/wiki/Aluminium)
"The low melting point of aluminium alloys has not precluded their use in rocketry; even for use in constructing combustion chambers where gases can reach 3500 K. The Agena upper stage engine used a regeneratively cooled aluminium design for some parts of the nozzle, including the thermally critical throat region."
There is also quite a bit of fire resistance data on the internet for Aluminium and Steel. The testing measures the degradation of tensile strength so the samples presumably have not combusted during the testing.
