First, I am a Jarrett Walker fanboy. Just no way around that. I think his doctorate in literature lets him think in a particular way about how planners think and talk. That’s what this whole article is about.
Interestingly, his aircraft analogy applies to other fields, too, when there are discussions of what is to be done; I see it in IT, for example. What I really like, though, how he fleshes out the analogy. I’ve been in many discussions where plane-crashers have derailed a high-altitude discussion (sorry for the mixed metaphors!).
Last, he’s obviously been to Norman! See the quote.
For example, if land use planning is nothing but development approval, then stuff will get built, project by project, without any attention to the aggregate consequences of that development — on traffic, on livability, on natural resources, etc.