In Susan Sontag's article "The Imagination of Disaster", she explains the cliches of science fiction films and how science fiction have less to do with science but more to do with disaster and "a good war". I believe her statement of seeking a "good war" to be true. From the various science fiction films I've seen, extraterrestrials are much more technologically advanced than us with their lasers, force fields, and hover ships capable of passing through the atmosphere unscathed. But for some reason, we're always able to fight on par against the invaders with our measly tanks and firearms.
Sontag states that most science fiction films follow the five phases of arrival, confirmation, national emergency, atrocities, and defeat of the invaders. Sure enough, most science fiction films follow this pattern because that's what the audience demands. The atrocities committed by the aliens give us a "reason" to fight "a good war" and the repulsion of the invaders solidifies our dominance as the human race.
A science fiction film I'd recall is Ender's Game. The main character is a talented boy who have graduated "Command School" with the ability to lead an entire fleet to wage war against extraterrestrials. This film also follows the phases shown by Susan Sontag but with one difference. The extraterrestrials were repelled from their initial invasion of earth with the destruction of their entire fleet but it doesn't end there. Humans formed a fleet to weed out the extraterrestrials to prevent future attacks and they succeeded by incinerating their planet with the "Molecular Disruption Device". But not all hope is lost for the aliens. The main character Ender Wiggins find the last survivor of the aliens and goes on a quest to revive them.