Battlefield Earth offers the satisfying spectacle of cave men in fighter jets engaging in dogfights with alien spacecraft. But we get ahead of ourselves.

This hilariously awful film begins in the mountains somewhere (we later learn it's Colorado). It’s the year 3000 and humanity is an "endangered species." A cave woman tells her long-haired boyfriend Jonnie that the "gods" took his father in the night. Jonnie emits a protracted, resounding howl of anguish.

Jonnie is dissatisfied with life in the caves. He's a "greener" -- the label given to one who believes the grass is always greener on the other side. He doesn't believe the tribal elders' warnings about "demons" and the "forbidden land." He leaves, after saying bye to his attractive girlfriend Chrissie (Sabine Karsenti).

But soon we are in a deadly serious firefight in a mall, where a dimly-glimpsed alien fires green blasts at Jonnie and his two new friends. Jonnie's horse is killed. He and his friends are captured. They are caged and flown to the Denver "Human Processing Center," which is run by 10-foot-tall aliens -- the Psychlos, of planet Psychlo. These rulers of Earth think humans are dumb brutes -- "man-animals," they call us.

Terl (John Travolta) is the security chief of our conquered planet. He's expecting a transfer home, but some bigwigs teleport in from Psychlo, and Terl learns he's stuck here. His dull-witted sidekick, Ker (Forest Whitaker), reminds him he has a "cushy job," but Terl thinks he was cut out for bigger things.

While the humans are being hosed down in cages and fed green glop, Terl hatches a scheme to mine gold in the mountains, concealing the profits from the Psychlo home office. But doing so requires teaching a man-animal to operate heavy equipment. Therefore Jonnie is hooked up to a Psychlo learning machine. He's taught the aliens' language, and given what seems to be a fairly good liberal-arts education.

The wide-ranging plot brings us to Fort Knox (where the humans simply pick up some gold, rather than mining) and to the Denver Public Library (where Jonnie reads the Declaration of Independence). It even brings us to planet Psychlo, target of a human suicide mission. Empowered by knowledge, Jonnie proves a highly formidable foe, one far more capable than the laughing, overconfident aliens ever imagined.

Amid a growing fury of unimpressive-looking explosions and debris, the rebel humans engage in bad acting and stilted dialogue. Chrissie, after following Jonnie from the caves, spends a lot of time silently wearing an explosive collar. Despite their primitivism, the humans speak in modern American vernacular.

The Psychlo roles are somewhat less thankless. Whitaker manages to give the simpleminded Ker a vaguely likable quality. Travolta is burdened with Terl's veritable caricature of villainy, but gives him occasional flashes of possible humor. ("That's why I'm a senior executive," he says, after one atrocity.)

Travolta bears the additional burden of having insisted that this movie be made.

Battlefield Earth is based on the novel by L. Ron Hubbard, the late science-fiction writer and founder of the controversial Church of Scientology (of which Travolta is a member). Travolta has said that this film does not advance the agenda of Scientology. Having viewed Battlefield Earth, it is hard to disagree.