It's a distinction the makers of Air Force One have taken to heart. (So has our president.) Air Force One is a textbook example of how to tell an unbelievable story in a believable way: get as many details right as possible, then let the actors, filmmakers, and crew suspend disbelief by creating their own illusion of realism--if "realism" is the right word for a tale that has the commander-in-chief steering a crashing plane and beating Commie asses in mid-flight. Remember that idiotic thriller Turbulence, in which the flight attendant wound up piloting a 747 solo while fending off a serial killer? Who'd have thought it would seem more plausible with the president of the United States in the cockpit?

Screenwriter Andrew Marlowe, that's who. Air Force One illustrates the theory of the Big Lie--the principle that a whopper is easier to swallow than a fib. Thus we have President James Marshall en route from Moscow, where he has just delivered a get-tough-on-terrorism speech backed by an ultimatum: no negotiation with terrorists, period. Such threats are catnip to terrorists, of course, and no sooner has Air Force One reached cruising altitude than a strike force disguised as a Russian TV crew whips out machine guns and herds the passengers into a conference room. Their demand: Release an imprisoned Russian nationalist general, or a passenger will be executed every half-hour--including the first lady (Wendy Crewson) and first daughter (Liesel Matthews).

But they don't get President Marshall himself, who slinks around in the plane's belly forming a course of action. As the vice president (Glenn Close) battles a near mutiny in the White House among the cabinet leaders, the president grabs a weapon and prepares to notch up some Reds. Meanwhile, U.S. jet fighters are dispatched into foreign airspace. The movie is a virtual love letter to gunboat diplomacy.

On paper, this must've read as complete lunacy--especially when the president starts duking it out with the Russkies in the cargo hold and dangles from the back of the plane. As written, the terrorists are faceless Commie creeps from a HUAC film festival, and leader Gary Oldman's pronouncements about Mother Russia superseding God are just one "pesky moosk" shy of Boris Badanov. And how do the terrorists slip past security? How do they secure a mole in Marshall's inner circle?

The director, Wolfgang Petersen, knows better than to linger over such matters. Instead, he focuses the early scenes on production designer William Sandell's painstaking recreation of AF1, a labyrinth of narrow corridors, secret passageways, and hidden compartments on three separate levels. The set provides a lot of credibility, and Petersen, the director of Das Boot, exploits it for all it's worth. By the time the terrorists seize control, the director has guided us so skillfully through the airliner's crannies that we know the layout. As a result, the movie's most hair-raising moments aren't the flashy, well-staged climaxes--a forced landing, an improvised midair escape--but the scenes of President Marshall inching through the plane's brightly lit aisles, expecting a bullet around each corner.

Apart from the trim craftsmanship and masterful editing (by Richard Francis-Bruce), what keeps Air Force One flying is a cast that refuses to acknowledge the implausibility of the material. Gary Oldman handles the psycho chores with a relish that should worry Dennis Hopper; Glenn Close makes a commanding veep, even though the script gives her little more to do than stand by her man. The supporting cast is packed with terrific actors: the great Philip Baker Hall shows up for about two minutes to explain the chain of executive command for the ages, and I felt better about the passengers after Fargo's William H. Macy stepped forward to demonstrate parachute safety.

In any other kind of movie, Harrison Ford's terse, tense, tight-lipped seriousness would be a real drag, but in action flicks his gruff intensity brings gravity and urgency to standardized mayhem. The defining moment in his career came in Raiders of the Lost Ark, when his exasperated Indiana Jones shrugged and blasted a showy swordsman; the surliness of that response marked Ford as an action hero audiences could sympathize with--the kind who'd rather be doing anything than saving his hide. That's the way he plays the most powerful man in the world--as a guy who wishes he could just veg on a couch and watch the Notre Dame game, if he didn't have the free world resting on his shoulders. The greatest thing about Harrison Ford as an action hero is that he knows how to take a punch. When he gets pitched into a wall by an assailant, he grimaces like someone knocked him loopy; he looks pissed off and a little scared of getting hit again. He humanizes some of the silliest superheroics just by looking worn out.

It's no slam at our sitting first executive that in Air Force One Harrison Ford makes a more believable president than Bill Clinton in Contact. Despite all their chortling about their CGI work, the makers of Contact spoil the realism of their movie, paradoxically enough, by pasting an actual public figure into an otherwise synthetic world. For one thing, we know the U.S. president isn't wasting our tax dollars by acting in a movie. For the movie's sake, it would've been better if he had: President Clinton's vague policyspeak sounds blander than usual with James Woods chewing the arm off the chair beside him.

In Air Force One, Harrison Ford sounds more presidential than the real Bill Clinton because he's part of the process--the illusion is seamless. But anyone who longs for Harrison Ford as our real-life prez should remember that we once had an actor play the president in the White House, and scarily enough, he gave us exactly what we demanded of him--a flickering image of authority on a blank screen. The day we get a real demagogue who knows how to marshal the forces of illusion is the day we feel the heat that singed Jean Seberg.