From Steven DeRosa’s Writing with Hitchcock:
A quote from screenwriter John Michael Hayes:
“…I remember one idea involving an automobile production line that never made it into the completed picture [North by Northwest]. The hero would arrive to question a production foreman. As the scene would begin, the foreman would point out a frame coming on the line and talk for a minute about the wonders of the assembly line. Then the questioning would begin and the two men would start walking. In the background, we’d see this frame being built into a car. After a few minutes, the necessary dialogue would be finished. But before the scene ended, the foreman would point to this car that the audience has seen assembled from a frame. The hero would go over, admire it, open the back door, and a corpse would fall out.”
From David Freeman’s Last Days of Alfred Hitchcock:
Occasionally, he would have ideas for film, or chunks of films, but no real story to hang them on. One beginning that amused him took place at the Metropolitan Opera House in New York. A performance of “Lucia” was in progress. When the soprano was at the height of the mad scene – he said he always imagined Callas doing it – and impossibly high notes are ringing through the great house, a shot is fired, its sound muffled by Callas’ voice. But it goes wrong and the man shot – he’s seated in a box – pitches forward and tumbles into the seats below. People scream, the orchestra stops playing, and the stage manager whisks the diva into the wings. We cut backstage to her dressing room. She’s pale and frightened. Her dresser and various assistants cater to her until she says to them all, “Please… thank you… but I must lie down. Thank you. Please go now.” Her attendants bow and depart. When she’s alone, she picks up her telephone, dials, and then says, “Well, it’s done. You almost botched it, but he’s dead.” That’s as far as he got.