In Recollections from the University of Vienna, given at New York University, 1962 (33:43), Mises says (my transcription):
“All universities in central Europe, continental Europe, are state universities. Even the idea that a university could be a private institution is foreign to most of these countries. And the universities are operated by the government, and of course they have — there is a fundamental difference between these universities and the other governmental institutions, the difference is — academic freedom.
“Academic freedom means that while all government employees and functionaries of the government are bound to obey in the exercise of their functions strictly what has been told to them by their — ordered to them by their — superiors, teachers at the universities — all teachers at the universities — and schools of the same rank (technological universities and today also commercial universities) are — and government employees who have no superior — they, nobody — not even the cabinet member representing duties of the supreme manager of instruction — has the right to interfere in any way with their teaching.
“This was/is of very great importance, of course, because there were in these countries again and again tendencies to influence the teaching of law and still more the teaching of economics and political science — social sciences in general.”
Recast with elipses:
“Academic freedom means that … [regarding] teachers at the universities … nobody … has the right to interfere in any way with their teaching.”
There are two points to note. Firstly, it is clear that Mises, in this lecture, is principally being descriptive, not prescriptive. However, it is also clear that Mises agrees that this ideal of academic freedom is the way that things should be. We can see this from his careful casting of the definition of academic freedom, which connotes a category of freedom defensible on principle.
Secondly, one cannot miss the fact that despite this official policy of academic freedom, the reality differed, and we know that Mises, for example, a proponent of what we today call the Austrian school, came to influence not as a professor, but as a privatdozent.