NOTHING about the businessman who strode on board the plane that day singled him out. Blending in perfectly with his fellow passengers, everything from his sunglasses, white shirt and dark business suit to the black attaché case he carried screamed corporate America. Yet halfway through the Boeing 727 flight from Portland, Oregon, to Seattle, Washington, the man, calling himself Dan Cooper, suddenly beckoned stewardess Flo Schaffner, and, opening his case, showed her what appeared to be sticks of dynamite and a detonator. He demanded $200,000 and four parachutes in return for the safety of his fellow travellers. When the plane landed in Seattle, Cooper was given the parachutes and the cash, worth more than £1million in today’s money, and set the 36 passengers free. With a skeleton crew, Cooper demanded the plane take him on to Mexico City. But in mid-air, somewhere over Oregon, Cooper donned a parachute, opened the plane’s rear door and, clutching the cash, jumped out.