Wikipedia says he says his latest "Essential Unified Process" "is a 'super light and agile'" Rational Unified Process, combining "the unified process camp, the agile software development camp and the process improvement camp." It's probably worth checking out.
To clarify however, I am not necessarily interested project management, I am interested in whatever methodology was used to deliver those projects successfully. Was it the methodology? Was it an unlimited budget?
If there was any methodology developed at the time, there must be some documented accounts. My example with the plane development method is only relevant in the sense that an "agile" methodology was used back in the '60s and it has been applied to software development relatively recent only.
Maybe there is more to be learned.
Ivar's work is perhaps more methodology than project management and an early version of his "Swedish Method" (as I like to refer to it :-) was used in the early '70s by Ericsson for their AXE phone switch that was (as reported by him) quite successful in the marketplace. It required a lot of flexibility so that they could customize it for N different markets, Sweden being quite small for that sort of product.