I remember reading many years ago that Air Canada acquired their fleet of B727s as a result of a superb selling job by Boeing in the early seventies. If my memory serves me correctly, Boeing sales did an in depth analysis of Air Canada’s route network, airports used, passenger levels and aircraft fleet. They then approached Air Canada with a recommended purchase of a certain amount of B727 that were, in their opinion, required immediately. I believe that AC disagreed with Boeing only in the number of aircraft required and, in fact, ordered more. Air Canada did order their fleet later than many other carriers.