The “About the Author” page at the end of Programming in Emacs Lisp says
Robert J. Chassell … has an abiding interest in social and economic history and flies his own airplane.
I love the childlike element of that bio. I could just imagine a kid saying “When I grow up, I want to read about history and fly my own airplane!” The bio is more about what the author enjoys than about how he makes his money. Maybe more bios should be like that.
The bio starts out by saying that Chassell speaks about Emacs and software freedom. I thought that was just to establish his bona fides for writing about Emacs Lisp, but his Wikipedia page says he’s a full-time speaker, so perhaps this is how he supports himself. I would not have thought that was possible, but good for him. Apparently he earns his living by talking about something he values.
Update: As suggested in the comments, perhaps Chassell’s livelihood does not come from his speaking. Maybe he has (or had) another career and chose not to include it in his bio. Or maybe he doesn’t need to earn a living from his speaking. In any case, it sounds like he’s doing something he loves and his bio focuses on that.
Of course, some have more than one full-time occupation.
Or, his personal situation is such that he doesn’t actually have to do anything to earn a living. Flying his own airplane sort of hints at that kind of existence.
Janne: True. I doubt speaking about free software alone would enable one to buy an airplane. :)
Or maybe, because he decided to do what he loves, he makes a better living at it.
Owning an airplane is expensive, for sure. But it’s not the sole province of the ultra-rich. The expense could easily be less than owning a second house (which may sound crazy to readers living in New York or California, but isn’t so rare in the cheaper parts of the country). So for a man who at some point in his life had a well-paying job and really really loves airplanes, it’s possible.