"The Flight That Fought Back" is not a scripted drama as such. It is not a pure documentary either.

Rather, the Discovery Channel special airing today about hijacked Flight 93 and the passengers who fought to take it back on Sept. 11, 2001, is a hybrid of reconstruction with actors, real dialogue drawn from public records and interviews with the loved ones of those who died when the United Airlines jet plunged into the Pennsylvania countryside.

As the film's narrator, actor Kiefer Sutherland, is careful to point out early on, "The Flight That Fought Back" is "informed speculation" about what took place aboard the San Francisco-bound plane that day as the passengers battled the terrorists and kept them from crashing the jetliner into their Washington, D.C., target.

What took place on United 93 is more fully documented than the events on any of the other hijacked flights. Numerous passengers and crew members were able to reach relatives, United ground personnel and others by cell phone, with some of those conversations being taped.

"In terms of screen time, about 50 percent" of the film is reconstruction, based largely on those phone calls, says Phil Craig, one of its executive producers. "In terms of what you're hearing, more like 10 percent.

"There are some dialogue scenes on the plane, and 90 percent of these are based on tape evidence and the memories of people who spoke to passengers on the flight. There are a very few occasions where we have invented dialogue," and they were "based on consultation with people who knew the passengers."

There's no question that "The Flight That Fought Back" — and Discovery — is treading on rather shaky ground. The gray area between documentary and drama is very touchy and controversial.

"Flight" also comes along at a time when, much to the dismay of documentary purists, more and more filmmakers are turning to re-enactments to fill in where no visual documentation is available.

But "Flight" makes re-creation its centerpiece. As moving as the interviews are with the loved ones of those on board, we have seen and heard them before. We also have heard the recorded conversations between those in the air and those on the ground.

What is different: Through their re-creations of Flight 93, the filmmakers put us on board the plane, creating a sense of the tension, terror and raw heroism. Even those who may have qualms about mixing fact and speculation are likely to find themselves caught up in the minute-by-minute retelling of the story.

One of the passengers on Flight 93 was Elizabeth Wainio, a young executive with the Discovery stores, and it's clear that Discovery feels a special obligation to her memory. Certainly, the filmmakers and Discovery have been very careful in the production of the film, taking every precaution to ensure accuracy and reaching out to the passengers' families for their cooperation.

They also avoid overplaying their hand in terms of drama, although one dream sequence toward the end of "Flight" comes very, very close.

"This is a profoundly, profoundly important action that was taken by these people, important for the whole of America, important for the whole of the world," says Discovery executive vice president Jane Root.

"That individuals who get up in the morning thinking they're going to have another ordinary day end up linking together and doing something as magnificent and as extraordinary as these people did is a truly wonderful thing."

Andrea Meditch, who oversees all of Discovery's documentaries, makes the point that this is one Sept. 11 story that could be lost simply because there is no visual history of what took place.

"One of the fears is that, as other events come into the public consciousness, what happened that day — particularly to those people on that flight — might be forgotten or might end up as a smaller part of our lives than it should be," Meditch says.

The film also gets strong support from Esther Heymann, Wainio's mother.

While acknowledging possible differences of opinion among the passengers' families about "Flight," Heymann says, "If I don't do another thing with my life, the most important thing that I can do is make sure this film is done right and that as many people as possible know about it."