The 39 Steps (1935)
dir. Alfred Hitchcock
North by Northwest (1958)
dir. Alfred Hitchcock
There's a little detail that announces Northeast by Northwest [sic], it's in the country when the policemen are hidden behind the rocks, there's a helicopter that passes and that heralds the plane later on in the other picture.
Francois Truffaut, Hitchcock/Truffaut tapes
