The air war in Iraq is, as expected, being waged somewhat differently than it was in 1991, even though a lot of the same aircraft and weapons are still around. There are about 900 bombers available, and about a thousand support aircraft. This compares to 1991, where there were 1600 combat aircraft and a thousand support aircraft. Back then, it was possible to fly up to 3,000 sorties a day, while in 2003, its about 2,000 a day, max. But because 70 percent of the bombs dropped in 2003 are smart bombs (versus eight percent in 1991), a lot more targets are destroyed per sortie. The U.S. Air Force has also finally learned its lesson about BDA (Battle Damage Assessment.) Every war since World War II featured the U.S. Air Force getting fooled big time by resourceful people being bombed. These deceptions were always found out after the war was over, and the air force muttered things like "we won" and "next time." But this time, a larger array of sensors overhead (high altitude Global Hawk and low altitude Predator UAVs, plus the satellites and JSTARS of 1991) made it possible to do two things that were impossible in 1991. First, Global Hawks and Predators can stay over the battlefield round the clock (working in shifts.) Second, these two UAVs provide live video (day and night) coverage of whatever they are looking at. The "persistence" and the harder to deceive live video made it much more difficult for the Iraqis to pull off all the deceptions that left the air force thinking they had destroyed far more enemy vehicles than was actually the case. Moreover, the ground and air campaign began at the same time in 2003, enabling the ground troops to quickly confirm, or not, what the air force thought they were seeing from the air. Partly based on the recent Afghanistan experience, the air force also pays more attention to how it uses air controllers with the ground units. The GPS bombs make it easier, and safer, to drop bombs close to ground troops, so this is done a lot more now. As a result of all these changes, including things like robotic bomblets dispersed from cluster bombs still in the air, it has become very difficult for the enemy to move combat vehicles at any time of the day. Estimates vary, but the new bombs and sensors make each sorties 3-5 times more effective than in 1993.