Lindsey Green has a theory:
Here’s the theory: In Green’s post, “Where Don Draper Ends, D.B. Cooper Begins,” she supposes that Don Draper is about to pull his most daring identity theft yet—he’s going to turn into a real, historical figure.
“D.B. Cooper” is the pseudonym of a man who permanently skipped town in November of 1971 by skyjacking a Boeing 727 in the most Don Draperian way a man could skyjack an airplane. Clad in a suit and tie, Cooper handed a note to a flight attendant. She presumed it was his phone number until he whispered over to her, “Miss, you’d better look at that note. I have a bomb.”
All I know is there are a ton of open-ended subplots and there’s no way they’ll all be tied up in last two episodes.
Knowing what what I know about Matthew Weiner, I can only assume this is all by design.