The four-engine prop DC-6B revved up its mighty turbines at the end of the runway with a tremendous roar. As the pilot released the wheel brakes, United Airlines flight 629 rolled down the narrow, bumpy tarmac gathering speed. The front wheel gently lifted from the ground as the nose of the aircraft pointed toward the heavens. Within moments, the sturdy airplane soared into the crystal blue sky and banked gracefully to the west, on its way to a 1,029-mile journey to Portland, Oregon. On board, Captain Lee Hall, an accomplished pilot and veteran of World War II, pulled steadily back on the control arm and within minutes, leveled off the plane at 4,000 feet. Visibility was good, and the crew, consisting of pilot, a co-pilot and three stewardesses, prepared for a leisurely flight over Colorado, Wyoming and Idaho.