The quantity of hijackings that occurred in the 1960s and 1970s is unfathomable today (as is the number of bombings). In fact, hijacking was not even a crime in the U.S. until the mid-1960s, so early “skyjackers” were charged with kidnapping instead.
The author of this book uses two strategies to better understand this phenomenon. The first is an epidemiological approach, pointing out copycat hijackings that are proximate in space and time to their inspiration. While this is true for both notable cases like D.B. Cooper and some minor ones, the approach is ultimately unconvincing.
Another device used in the book is a focus on the 1972 capture of a Western Airlines flight. It is not entirely clear why this particular incident was chosen, but the two protagonists (Roger Holder and Cathy Kerkow) are interesting characters. This was also one of the first occurrences with a team of hijackers, and at the time it set a record (quickly broken) for the most ransom money elicited from an airline.
One interesting historical sidenote is how opposed airlines were to stricter airport security. They viewed the all-in cost of recovering a hijacked plane ($20,000 including making amends with passengers, diverting traffic, and giving crew members extra vacation days) as doing less damage to their business than the delays caused by extra screening. Moreover, they were probably correct; William Landes calculated, in a landmark study, that deterring a single skyjacking cost about $9.25 million, or nearly 20 times the record-breaking amount that Holder and Kerkow obtained (a large portion of which was quickly returned by authorities).