"Plane change maneuvers are expensive" is the one I remember off the top of my head, but I do distinctly recall another line elsewhere in the book. Sorry I can't be more specific.
Why bother? It's not like Stephenson invented that sentence. It's a fact, stated in the simplest possible way. If you google that literal sentence, you'll find quite a few uses unrelated to his books.
Want to take a swing at that yourself? I did do some google searches for the phrase in question, and other people have used it online (though I admit all the citations I found in my cursory search date to after Anathem, though that is no guarantee that they are aping it.)
I noticed a lot of parallels between Snow Crash and Anathem. Both had dialogues meant to educate the reader, and there is a little overlap in the concepts explored in both books.
