A flag on screen is a shortcut. It tells an audience whose side they are on, or which side they are being asked to distrust, without a line of dialogue. That efficiency is why directors, showrunners and artists keep reaching for them, and why the same piece of cloth can mean patriotism in one film and indictment in another.
Flags in movies
War films use the flag for patriotism most directly. In "Saving Private Ryan" (1998) the American flag carries the themes of sacrifice and duty, and the final shot of it over Captain Miller's grave is the film restating the cost of what came before.
Turn it around and the flag becomes the rebellion. The red flag in "Les Misérables" (2012) belongs to the fight for freedom and justice during the French Revolution. In "V for Vendetta" (2005), the Guy Fawkes mask usually appears alongside the red and black of anarchy, marking the protagonist's campaign against a totalitarian state.
Invented flags do the same work for invented places. "Black Panther" (2018) gives Wakanda a flag, and it stands in for the nation's history and its technological advancement in a way exposition would take minutes to establish.
Flags can also be the joke. In "The Great Dictator" (1940), Charlie Chaplin gives the fictional country of Tomainia a flag that resembles Nazi Germany's closely enough to make the resemblance the point, and the satire works because the audience recognizes the shape before the argument.
Flags on television
Television gets flags in bulk during national events. Olympic medal ceremonies are built around raising them. In "The West Wing" (1999-2006), the American flag is a constant background presence, which suits a show about governance and national identity.
Political dramas use flags to point at the gap between the symbol and the behavior. In "House of Cards" (2013-2018), the American flag turns up around power struggles and ethical compromises, and the opening credits run a time-lapse of it over Washington, D.C.
Flags can also signal cultural range. "Modern Family" (2009-2020) occasionally puts flags from various countries into scenes to mark the characters' heritage.
Fantasy and science fiction build whole political systems out of them. In "Game of Thrones" (2011-2019), the banners and sigils of the houses, the Stark direwolf and the Lannister lion among them, carry allegiance and power. They are how a viewer keeps track of who is fighting whom across Westeros.
Flags in art
Artists tend to use the flag as a thing to argue with. Jasper Johns' "Flag" (1954-55) reinterprets the American flag in encaustic, and the effect is to make viewers look again at an image they had stopped seeing.
Protest art goes further. Dread Scott's "What is the Proper Way to Display a U.S. Flag?" (1989) laid the American flag on the ground and invited viewers to walk on it while writing their responses in a book. The piece provoked strong reactions and pushed a public argument about free expression and what national symbols are owed.
Flags also carry dual identity. Chicano artists have combined or reimagined the Mexican and American flags to work through the experience of being both, and those pieces get at the awkwardness of assimilation as much as the pride.
Ai Weiwei's "Study of Perspective" series shows the artist giving the middle finger to landmarks, national flags included, using the gesture to criticize political oppression and the authority of nation-states.
Across all three media the flag is doing one job in different registers: it stands for something large, and the artist decides whether to endorse it, complicate it, or hold it up for ridicule.