Hawkman and Superman learn a lot about each other in this issue. Welcome to the JLA, Carter!
The story: "Attack of the Star-Bolt Warrior!" by Gardner Fox, Mike Sekowsky, and Bernard Sachs. The debut of a new villain, the goofily-attired Brainstorm, who forces the JLA--or some of it, at least--to watch as he executes Green Lantern for the murder of this brother!
Roll Call: Superman, Batman, Flash, Green Lantern, Atom, Hawkman
Notable Moments: Brainstorm debuts in what will be the first of many appearances in the DCU.
I think Fox felt a lot more comfortable writing Hawkman, since he appeared a lot in subsequent issues, much moreso than a lot of the older members.
The letters page header changes again. Atom is still not re-drawn, but Hawkman has been added, by what looks like Murphy Anderson:
...it's getting crowded in there!