I'm surprised that no one has yet mentioned A Long Strange Trip - Dennis McNally's rather wonderful boigraphy of the Grateful Dead. As you'd expect, there are numerous references to the Airplane in there, including probably the best account I've ever read of the whole mid 60's/San Francisco/Summer Of Love scene. He really captures the spirit of those times so vividly.
There's also a fascinating and quite detailed account of the whole Altamont debacle, which takes up most of a chapter, and is much more comprehensive than the paltry three pages devoted to the subject in Jeff Tamarkin's Airplane biog.
Finally, Susan, on a slightly different note, I completely agree about Kirby's Thor comics. I also loved Ditko's Dr. Strange - arguably some of the weirdest stuff ever printed in mainstream comics.
My particular favourite, though, remains Will Eisner's Spirit. It's stood the test of time remarkably well in many respects, and in terms of pure storytelling, it remains a benchmark.