Flag Drop

Where the hero poses in front of (or next to) a prominently shown national flag.

Any sort of overly patriotic (or even generically heroic) speech will have the flag slowly descending into view behind the speaker and some music (usually the Dambusters march, for some reason) slowly rising to match.

This use of the American flag can become Narm very easily, especially outside the United States.

Largely a subtrope of Patriotic Fervor. Compare Wearing a Flag on Your Head.

Examples of Flag Drop include:

Anime

This is seen in the world conference in Axis Powers Hetalia, here. Also:

America: I'M THE HERO!

Film - Animated

Toy Story 2 has Buzz Lightyear give an inspiring speech as a waving flag appears in the background and "The Star-Spangled Banner" plays. This fades into the next scene, where Al is watching TV with the American flag on it. Averted in the international version, where the flag is substituted by a spinning globe, with a generic musical theme playing instead of the American anthem.

Film - Live Action

A scene in Patton (as shown in the page image) is the Trope Codifier, to the point where most modern examples are parodies of it.
In Spider-Man 3, immediately before Spidey springs into action to save New York from Venom and Sandman, he takes a moment to stand impressively in front of a ridiculously large American flag lit by an unknown source of light in the middle of the night.
Near the end of The Rocketeer, there's a scene where the character stands in front of an American flag and has a spotlight shine on him before a dramatic fiery takeoff. For better or for worse, he's about to go fight some Nazis.
Small Soldiers has Chip Hazzard stroll in front of an American flag... or rather, a jigsaw puzzle of one, since the Commando Elite are all in a toy store at this point. The speech he gives is composed entirely of quotes from famous patriotic speeches.

Live Action TV

In one episode of Frasier, as Frasier was giving an inspirational, quasi-patriotic speech, a giant American flag suddenly dropped in front of the windows of his apartment.

Niles: How did you do that?

Theatre

In the musical Chicago, Billy brings on Uncle Sam to drape an American flag behind Roxie during his Chewbacca Defense closing argument.

Western Animation

In The Powerpuff Girls episode "Collect Her", this happens when Professor Utonium tells Lenny Baxter that a true fan should set the girls free.

Utonium: Free to do the things they do best. To do the things we love most about them.