JDAM (GPS satellite guided bombs) . . . entered service in time for the 1999 Kosovo campaign, and have been so successful, that their use has actually sharply reduced the number of bombs dropped, and the number of sorties required by bombers. . . . After the invasion of Iraq, the U.S. Air Force ordered a sharp increase in JDAM production, aiming for 5,000 JDAM a month. They ended up needing far less. In 2005, about 30,000 JDAM were ordered. That fell to 11,605 in 2006 and 10,661 in 2007. This year, only 5,000 are being ordered. Nearly all those ordered in the past few years are being put into the war reserve. Only a few thousand a year are actually being used, and this includes those expended during training. . . .
While guided bombs first appeared towards the end of World War II, they did not really become a factor until highly accurate laser guided bombs were developed in the 1960s. A decade later, TV guided bombs came into service. But these guided bombs were expensive, costing over $100,000 per bomb. Even as late as the 1991 Gulf war, only 16 percent of the 250,000 bombs dropped were guided. But analysis of the battlefield later revealed that the guided bombs had done 75 percent of the actual damage. But the guided bombs were still too expensive, and lasers were blocked by many weather conditions (rain, mist, sand storms). . . . The current price [of JDAMs] is still under $30,000 each.
[I]n the 1999 Kosovo campaign . . . 98 percent of the 652 JDAMs used, hit their targets. In 2001, JDAM proved the ideal weapon for supporting the few hundred Special Forces and CIA personnel the U.S. had on the ground in Afghanistan. The JDAM was more accurate, and effective, than anticipated. By January, 2002, the U.S. had dropped about half their inventory, of 10,000 JDAMs, in Afghanistan.
In 2003, 6,500 JDAM were used in the three week 2003 Iraq invasion. Since 1999, American aircraft have used less than 25,000. . . . The latest versions are even more accurate, putting half the bombs within ten meters of the aiming point. . . . With the ability to put a weapon within a meter of the aiming point (using laser guidance) or 5-10 meters (using GPS), smaller is now better, especially in urban areas where there are a lot of civilians about. But even without civilians around, smaller, more precise bombs and missiles are preferred, as that allows friendly troops to get closer to the target, and rush in right after the explosion, to finish the job. Troops have changed the way they fight because of this. There is more movement in urban warfare because of all this precision firepower, and fewer friendly fire casualties from bombs and artillery.
The article goes on to note the increasing use in the military of several kinds of small guided weapons by the Army, with tens of pounds of explosives. The author attributes this technology to a change in tactics by forces facing American troops:
In Afghanistan and Iraq, the enemy largely gave up trying to fight American troops head on. Ambush, roadside bombs and boobytraps became the preferred methods of attacking U.S. troops.
The impact of smart bombs on the number of aircraft required by the U.S. military isn't quantified, although the figures provided from the Gulf War suggest that the number of bombs that need to be dropped has fallen by about 94%. This number surely isn't a number that the Air Force is eager to publicize, nor is the fact that drones and various guided weapontry used by Army troops can now often substitute for aircraft in a way not previously possible. Also, smart bombs allow aircrft dropping them to be less sophisticated, because they don't have to get as close to their targets, which may have anti-aircraft weapons, and smaller, because the bombs that are being dropped can be smaller and fewer need to be carried per sortie. Likewise, the historical fact that the U.S. has had unquestioned air superiority for most of its recent combat experence, argues that there may be considerable room for less sophisticated bombers.
Clearly, the Air Force ought to be able to do more with less, which means that military procurement should assume a major drop in Air Force spending (or at least the number of aircrft in the Air Force fleet).