The second biggest question of the war—after "Where is Bin Laden?"—is "Where are the Stingers?" (Strangely, no one in the press is asking the latter.) Early in the war, the Pentagon stated that some 200 to 300 of these U.S.-made shoulder-launched surface-to-air missiles remained in Taliban and al-Qaida (TAQ) hands, leftovers of the 1980s U.S. program that had supplied them to anti-Soviet mujahideen. (Read a Slate story about the history of that missile program here.) This was a real concern because the Stingers are the TAQ's most sophisticated anti-air weapon—the mujahideen completely turned their war versus the Soviets around by using them to devastating effect against Moscow's helicopters. Also, because these missiles are guided by an air target's heat energy, they don't have radar that can be detected or jammed. And because the missile-launcher package weighs only 35 pounds, Stingers are completely man-portable. At any given time, they could be anywhere. So why haven't they been a factor in the war so far? There are several possibilities.
Their warranty expired. Stingers are supposed to have a shelf-life of 10-12 years. The Afghans have had them since the mid- or late-1980s, so maybe theirs just don't work anymore. But there's evidence that they do: Stingers reacquired by the United States from Afghanistan via a buy-back program have consistently worked when tested.
The wad has already been shot. Maybe in the initial stages of the U.S. air campaign back in October, the TAQ forces unleashed all or most of their Stingers. (If they did, we probably wouldn't know it—Stingers don't put out a radar signal, and at night, when most of those early U.S. airstrikes were carried out, pilots wouldn't see their smoke trail.) This wouldn't have been very smart, because Stingers are almost useless at night: The operator must visually track the target aircraft long enough for the missile's heat sensor to lock on. (And the TAQ fighters don't have night-vision devices.) But it wouldn't have been unprecedented either—a pronounced lack of fire discipline is a common feature of Third World militaries. The night airstrikes of the first days of Desert Storm were also met with profuse but mostly useless Iraqi anti-air fire. If you are in somebody's (very accurate) bombsights with a weapon at your disposal, there's a powerful and very human urge to use it even though it probably won't do you a bit of good.
The Stingers have already been stung. Maybe TAQ fire discipline was just fine, but they lost all or most of their Stingers because the shoulders they were to be launched from got separated rather suddenly from the adjacent heads or because the warehouse(s) where they were being stored got blown up. This, too, is not unprecedented. In World War II, most of the Germans' best air weapons—their jet fighters, by far the war's fastest planes—were destroyed on the ground.
They're safe and sound, but useless. Knowing that the Stinger is far and away their blue-chip weapon, the TAQ forces may have kept them from being launched or destroyed by moving them to their securest areas—mountain caves. But once there, the missiles really can't be used, at least not until there are U.S. aircraft flying nearby. Don't smirk at this one—our highest value weapon, the B-2 Stealth Bomber, has flown all of about six missions and can't seem to spend the night away from its home base in Missouri.
They're lying in wait. The possibility that should give U.S. war planners the most concern is that their TAQ counterparts are simply waiting for more suitable targets. Maybe they're well aware that their Stingers are basically useless at night and against tactical jet aircraft (which can either fly above the missile's ceiling of approximately 10,000 feet, or come in too low and fast for the missile operator to draw a bead on them). TAQ troops might even understand that the special operations helicopters that have seen the bulk of U.S. low-level air action so far have infrared countermeasures against Stingers—such as devices that suppress their heat signature and the ability to shoot flares that can divert a heat-seeker—that Soviet helicopters generally lacked. So, the TAQ might be waiting for the larger and more unsophisticated troop-hauling choppers favored by our conventional forces, not to mention for the lumbering jet transports that do the bulk of the Army's and Marines' logistical work. If I were the last al-Qaida fighter with a Stinger left in Afghanistan, with the same willingness to die exhibited by the 9/11 gang, I might wait in the weeds—even until long after the war is "over"—for an American plane landing with food packages or a USO troupe or a delegation from Washington.