In Libya, NATO (mainly French and British) fighter-bomber pilots are learning a hard lesson about how effective ground troops can be at hiding themselves from air attack. The Libyan forces have quickly adapted to an enemy that controls the skies, and is armed with highly accurate smart bombs and missiles. One of the obvious ploys is to move troops and munitions in civilian vehicles. The Libyan forces are also using camouflage, and other deceptions to escape attack. The main problem is that the bad guys on the ground have more incentives, and more opportunities, to deceive the warplanes up there. NATO pilots are being reminded of this on a daily basis.
This sort of thing has been a major problem since World War II. Despite 70 years of efforts to better detect enemy forces from the air, the people on the ground still manage to avoid getting found and hit. Intelligence capabilities were still not up to the task of accurately finding targets, or measuring the impact of the bomb strikes afterwards.
Blame it all on BDA (Bomb Damage Assessment). This is the business of figuring out what to bomb, and what the impact on the enemy is after you bomb. The problem, of the guys in the air getting fooled by the guys on the ground, began in earnest during World War II. This was when air forces used large scale aerial bombing for the first time. Right after that conflict, the U.S. did a thorough survey, of the impact of strategic bombing on Germany and Japan. It was discovered that the impact was far different from what BDA during the war had indicated. The air force vowed to do better next time.
But as experience in Korea (1950-3), Vietnam (1965-72), Kuwait (1991) and Kosovo (1999), Iraq (2003) and Lebanon (2006) demonstrated, the enemy on the ground continued to have an edge when it came to deceiving the most energetic BDA efforts. The only proven technique for beating the BDA problem was to have people on the ground, up close, checking up on targets, while the fighting was going on. Before the 2006 war, the Israelis did not want to do this, because of the risk of some of their commandos getting killed or captured, and because the intel and air force people were sure that they knew what Hezbollah was up to down there. This is why NATO wants to get special operations down there, and risk of losing any of these elite troops is the main reason the leaders of NATO countries don't want to do it.
But there's another problem. The army and air force have a different outlook on planning and risk. The air force sees warfare as a much tidier, and predictable, affair than does the army. In this respect, the air force and navy are closely aligned. Both are technical services, who are used to exercising more control over their forces than do army generals. The army sees warfare as more unpredictable, and has adapted to that unpredictability. Before 2006, the Israeli army generals were skeptical of the air forces ability to take down Hezbollah from the air, and the army guys proved to be right. The army is still right, as NATO pilots are learning in Libya.