A provocative feature film called “United 93” is causing a stir weeks before it opens April 28 around the country. It’s about the fourth hijacked plane that crashed on Sept. 11, 2001, and an emotional debate focuses on whether it’s too soon for a Hollywood treatment of that turning-point day. A Manhattan theater stopped showing the preview trailer after complaints.

The real United Flight 93 crashed in a Pennsylvania field after 40 passengers and crew members fought back against terrorists in the cockpit. That drama was depicted in a January cable TV film, but the new release will be the first feature film dealing explicitly with the attack on America less than five years ago. Its trailer shows hijackers with explosives rushing the cockpit, panicky passengers using cell phones and the unforgettable video of another plane flying into the World Trade Center.

Writer-director Paul Greengrass, who also made "The Bourne Supremacy," gained approval from each victim's family. Still, questions are being raised in newspaper columns, blogs and online discussion forums: Is it too soon? Is Hollywood cashing in improperly on our national trauma? Will a mass audience want to see it?

Critics say: "This film disturbs me. I already saw it once -- I watched it live," editor Neil Miller writes on his blog, Film School Rejects. Dahlia Lithwick, senior editor of the online magazine Slate, notes that audiences attending another film don’t expect to see "a shocking movie trailer . . . something utterly scarring." She adds: "We need to concede that 9/11 really is different, and to be a bit more careful of sensibilities." A colleague, Slate associate editor Michael Agger, agreed in a discussion posted last week: "For those who lost someone on that day, the 9/11 footage is not 'news' or 'history.' It's the replay of a murder. . . . Watching that is much different than seeing a fictional re-creation of a horrific event. . . . The creators of 'United 93' are playing with raw materials. This is not the stuff that Hollywood dreams are made of."

Defenders say: "This story has to be told to honor the passengers and crew for what they did," says Carole O'Hare, whose 79-year-old mother died on the flight. Slate foreign editor June Thomas comments: "We can’t put some experiences off-limits." A statement from Universal Studios says, in part: "We expect that some moviegoers will have a strong response. . . . [The trailer is] truthful and direct so that those who elect to see the film will be prepared for the experience." The studio will give 10 percent of its opening weekend gross revenues to the Flight 93 National Memorial Fund.

Behind the issue: In an odd overlap, Flight 93 also is making news as part of a federal court hearing to decide whether convicted terrorism conspirator Zacarias Moussaoui will be executed. Jurors in Alexandria, Va., soon will hear cockpit recordings from the United jet and see transcripts of those tapes. Critics of the film say that shows why it’s inappropriate. "We don’t know what happened on that airplane, but whatever happened, it’s not entertainment," says Agger of Slate.