It is unlikely that if thermite were present that any of it would remain uncombusted. And combusted thermite amounts to what? Iron and aluminum oxide. And what do you expect to find when an aluminum airplane burns in a steel-framed building? Aluminum burns just fine in the right environment, releasing more heat than jet fuel. It is used all the time in solid booster propellant.
It is unlikely that if thermite were present that any of it would remain uncombusted. And combusted thermite amounts to what? Iron and aluminum oxide. And what do you expect to find when an aluminum airplane burns in a steel-framed building? Aluminum burns just fine in the right environment, releasing more heat than jet fuel. It is used all the time in solid booster propellant.