When the plane lands, there is an announcement, "Welcome to Paris Charles de Gaulle. Bienvenue à Paris Charles de Gaulle." Of course, in real life, the pilot would state things like time and temperature, which would be too long for a TV episode. But Charles de Gaulle Airport is not, in fact, in Paris. It's in nearby Roissy. Non-Parisians refer to it as Charles de Gaulle, Parisians tend to just call it Roissy. It is usually referred to on planes as "aéroport de Paris Roissy Charles de Gaulle" or "Paris airport Roissy Charles de Gaulle," or something similar. But it's always called Roissy, because that's where it is.