‘Flatliners’ Leads Lively Box Office : Movies: Young audience helps medical drama and Gibson’s ‘Air America’ shoot down Nicholson’s ‘Two Jakes.’

Mel Gibson’s fans came out but Jack Nicholson’s didn’t.

That’s the conclusion many film industry analysts are drawing from the fact that the Mel Gibson action comedy “Air America,” a movie that was largely panned by critics, did strong opening-weekend business, while the Jack Nicholson mystery, “The Two Jakes,” which received mixed reviews, qualifies as a flop.

Paramount Pictures’ “The Two Jakes,” the long-delayed sequel to 1974’s revered “Chinatown,” grossed $3.7 million at 1,206 theaters, for a per-screen average of $3,092--and a seventh-place ranking among films in release. Tri-Star Pictures’ “Air America,” which stars Gibson and Robert Downey Jr. as pilots in a secret CIA operation in Laos during the Vietnam War, took in $8 million at 1,902 screens for $4,240 per screen and third place on the box office chart.

But the biggest winner among new releases was Columbia Pictures”’Flatliners,” which earned $10 million on 1,319 screens--for an average of $7,608 per screen and the No. 1 spot. Starring an ensemble of popular young actors, including “Pretty Woman’s” Julia Roberts, and bolstered by heavy television advertising--and a trailer that made its way into theaters in the spring--the film about medical students who venture into near-death experiences apparently helped fill a youth-oriented void in the late summer market.

In fact, according to Cinema Score, which tracks moviegoers’ opening-night responses, 64% of those who attended “Flatliners” were younger than 25. That portion of the audience gave the film an “A” rating (overall, the film drew a “B+”). “That’s the kind of crowd you want. That’s the kind of crowd that gives you repeat business,” said spokesman Harold Mintz.

In comparison, 38% of those who attended “Air America”--which rated a “B” overall--were younger than 25. And of those who attended “The Two Jakes”--which drew an overall “C+”--only 13% were younger than 25.

Of the continuing titles, Paramount’s “Ghost” held on as the summer’s surprise hit. Though the film dropped to second place, it earned another $9.4 million ($5,353 per screen), bringing its total grosses, after five weeks, to $85.4 million. And Warner Bros.’ courtroom thriller, “Presumed Innocent” continued its impressive performance with ticket sales of $7.9 million ($5,446 per screen) for fourth place.

But the dismal performance of “The Two Jakes” was the most startling box office news of the weekend. The sequel to “Chinatown” had been in the news for years. It was initially set to begin production in 1985 when screenwriter Robert Towne, who was set to direct, decided he couldn’t make the film with producer Robert Evans on screen in a key role. Paramount pulled the plug on the project at the time, and it wasn’t until Nicholson agreed to direct, as well as star, that it was revived.

Whether the film relied too heavily on its long-ago “Chinatown” roots or skewed beyond the range of audiences too young to care about private eye Jake Gittes, there was little interest in the $24-million sequel.

Paramount promoted the movie with advertising that leaned heavily on Nicholson’s presence, as opposed to the story. The ad line (“They say money makes the world go ‘round. But sex was invented before money”), emphasizing salable elements that are barely in the movie, didn’t work.

At the same time, the confusing television campaign for “Air America” (which never satisfactorily explains just what the movie is) and a wave of mostly caustic reviews failed to deter people.