The Mysterious Man in the Flying Machine Department S : Season 2 Episode 10

After the voice of an airline pilot announces to the passengers that they are on their way to Athens, one of the travelers turns around and shoots another one through the back of his seat before exiting by jumping off the plane - onto solid ground. He is then pursued by other 'passengers' but escapes. The whole plane set is a mock-up built in a Paris warehouse, and when local police, alarmed by the shots, find it, the Department 'S' team is called in to investigate. A message scrawled in lipstick on the windshield of Stewart's car leads them to a girl - who is murdered by the assassin from the 'plane' before the team can talk to her. Finally they come to believe that the entire charade was a rehearsal for an assassination.