BIRDY" is a dizzying myth of resurrection and true friendship set against a backdrop of modern war. Matthew Modine, in the title role, plays a disturbed boy who rises above the squalor of Philadelphia in schizophrenic dreams of flight, but falls to earth from a helicopter in the nightmare of Vietnam. Missing in action for a month, he returns a cowering mute.

Nicholas Cage costars as his close friend Al, another blue-collar boy who goes to war where he too is wounded, but in a physical way. Their mutual recovery is the focus of this overwrought but often eloquent film.

Like the Vietnam Memorial, it is haunting, disquieting, absorbing. But as with that monument, some people will want something easier to understand, more earthbound. John Wayne understood.

Al admires Wayne, but doesn't expect the realities of war. He goes off in his khakis, a jaunty, sure, all-American lady- killer and returns with his face in a sling. "I'm a little scared I won't recognize who I'm shaving in the morning," he confesses to Birdy in the hospital. So he stays to coax his friend back to reality, reminiscing over high school days, memories that precipitate a series of flashbacks in Birdy's mind, of capturing pigeons, of building an ornithopter, of buying a tiny yellow bird.

The actors face great challenges: Cage his bandages, Modine the silence. Portraying a catatonic schizophrenic, Modine uses only his body, with his arms tucked under like wings and his feet clutching at the railing of his bed like claws. It seems he has become a bird.

While Modine's contortions are memorable, Cage too often can only mumble. But free of his bandages, he is human and warm, a big meaty Italian boy in flashbacks which establish a portrait of an enviable friendship interrupted by war.

"Birdy" is a sky-colored film, full of blue, white and cloudy grey, a film frequently shot from overhead or with a bird's eye. And there are exhilarating sequences as the camera imagines a shaky first flight in Birdy's torn mind.

However, director Alan Parker, whose other films include "Midnight Express," "Fame," and "Shoot the Moon," is too studied here. The scenes are mostly lovely vignettes, but reach too often for symbolism. Frequent references to both the crucifixion and the Pieta are far more than this intimate a movie can bear. Continual references to bars and cages also belabor the point. It is nevertheless an interesting vision.

After two hours of a movie like this, a movie set in a mental hospital, a movie about the horrors of war, you ought to feel emotionally drained but spiritually restored. You ought to have learned, or relearned, some great truth. But it ends vacantly, like feathers loosed on the wind; memories are soon flown, soon forgotten.

BIRDY (R) -- At the Circle MacArthur.