The first scenario is more consistent with the evidence as a whole. The second requires a level of sustained discipline over a very long time that most investigators consider improbable but not impossible.
The diatom analysis from 2020, suggesting the bills entered the water months after the hijacking rather than immediately, adds another wrinkle. If the bills went into the river in spring 1972 rather than November 1971, someone or something moved them between the jump and that deposit. How they got from wherever Cooper landed to the Columbia River system, and when, is not established by any evidence.
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## A Profile That Fits Many and Identifies None
One of the most discussed aspects of the Cooper case in amateur and professional circles is the question of what kind of person could have planned and executed this hijacking.
The planning, such as it was, was minimal. Cooper bought a one-way ticket with cash. He chose a short, specific route—Portland to Seattle—and a plane type that gave him specific tactical options: the Boeing 727’s aft airstair was the key feature he exploited, and this was not public knowledge but was known in aviation circles. He demanded parachutes rather than a specific escape vehicle, which gave him options. He gave instructions for the flight south that suggest some knowledge of aircraft performance limitations.
Several things about the hijacking suggest familiarity with aviation or military experience. The demand for four parachutes (rather than just one) is one: it may have reflected a negotiating tactic—if he had only asked for one, authorities might have tried to give him a defective one. Requesting four made that more difficult. His instruction about flying below 10,000 feet unpressurized and at reduced speed shows some knowledge of aircraft capability. His use of the aft stair—a specific feature of the 727 that allowed mid-flight deployment—has led most analysts to conclude he knew about it in advance.