The song was the title track from the 1969 album which was the group's last. Co-founder Balin and drummer Spencer Dryden left after its release while Jack Casady and Jorma Kaukonen split off to form the unfortunately-named Hot Tuna. (I read somewhere that Kaukonen originally wanted to call the new band "Hot Shit" but the suits at the recording studios understandably objected.)
...was originally intended to be Volunteers of Amerika, a corruption of Volunteers of America, an American version of the Salvation Army charity; the term 'Amerika' was then in vogue as a sardonic expression of dissatisfaction with the USA. However the charity objected, so the title was shortened to Volunteers.
The song (my emphasis):
...is a call to take a stand against the US government and the war in Vietnam. In a 1993 interview with Relix, Balin explained: "It became political but it didn't start out that way. I had woken up to the sound of garbage cans crashing outside the mansion and looked out, and there was this Volunteers of America truck, so I wrote that down and gave it to Paul and he wrote the song. Bang. People put all kinds of meaning into it."
It's funny, the inspiration for many of the Airplane's songs -- science fiction novels, everyday annoyances -- were quite a bit removed from what people like my parents most feared from rock 'n' roll in the 1960s: anarchy, revolution, nihilism. Maybe the music just sounded good. Still does.