It’s not a typeface ('font' has become a common term, but it’s inaccurate, as it addresses a specific weight or variation of a type family) – rather it’s skillful handlettering, and it’s due to Sol Brodsky (most of the early Marvel logos were his work), which was part of the original "Marvel bullpen", as Stan would have later put it.
I'm just now seeing this. Thanks for the drop of knowledge!
You’re welcome. Actually I believe that Sol Brodsky here was able to convey the "sense of wonder" which belongs to early american science fiction and the like. The 1960s aesthetics is more "industrial", and the FF and early Marvel covers had that "magic" that was generally lost in the following decade.