The U.S. Air Force has a well-deserved, and understandable, reputation for advocating military victory achieved mainly with air power. They still do, in spite of a historical record that will not cooperate. That said the air force have some solid accomplishments to its credit. In some areas it has been extremely successful. This includes gaining (since 1945) and maintaining (ever since) air supremacy wherever it operates.
But when it comes to influencing the war on the ground the air force is much less dominant. 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 air force leaders being deceived by the people on the ground being bombed, began 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. Those with powerful air forces do 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 enemy as up to down there.
The people on ground have consistently demonstrated an ability to deceive aerial surveillance. Even during the early 21st century, when the U.S. developed persistent UAV surveillance the irregular forces they were facing proved capable of reducing the effectiveness of the UAV effort. This spotlights another useful fact; air power can be useful on the ground but that happens over time and not quickly. The problem here is with voters and the media. Both demand quick victory and in the U.S. that has developed into the “three year rule” in that public support for a way no matter how enthusiastic it was at first, is largely gone after three years. If an air campaign can’t get it done in three years that effort comes under media and political attack no matter how effective it has been.
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. The army generals are usually skeptical of air force ability to take down foes from the air and the army guys are usually right.
Despite being a successful high-tech outfit American air forces (especially the Navy and USAF) frequently have trouble adjusting to changes it does not agree with. Thus when the Cold War ended in 1991 the air force was still largely thinking about continuing to operate as they had done in the Cold War. But the technology and tactics of warfare were changing. The post-Cold War enemy was no longer large organized forces spread over huge areas. The foe was increasingly irregulars who were harder to spot from the air. The air force reluctantly adapted, in part because the army and CIA adopted new reconnaissance and surveillance techniques, like UAVs and constant surveillance.
As successful as these new air reconnaissance tools were they did not seem like a suitable long-term job for the air force. The other services disagreed and it took the better part of a decade after 2001 to get the air force to come around. In 2005 the air force deployed its first Predator UAV unit and in 2009 it put its first Reapers to work. They were following the CIA in this area, which caused some misgivings among senior air force leadership. But the army and Congress were calling for more of what the CIA was doing (armed UAVs for surveillance and attack) and the air force joined in.
What the CIA has pioneered was “persistent surveillance” with armed UAVs. The 24/7 observation by the UAVs enabled CIA or air force intel analysts to compile information about the target and order one or more missiles fired as soon as the key target was identified and located. This led to an ever growing list of terrorist leaders and their key subordinates killed in this way. At the same time this use of surveillance and precision weapons led to lower collateral (nearby civilian) casualties to plummet to historical, and remarkable, lows.
Air force traditionalists warned that in a conventional war this sort of thing would not work. Where the enemy had modern air defense systems and jet fighters the Predator and Reaper UAVs would be impractical because they would be quickly shot down. But that is not the type of war being waged now and it is pointed out to the air force that the military has to deal with what they are faced with, not just with what they prefer. Moreover, even in a “conventional” war there is still work for these new tactics and the tech that makes it possible. The air force still disagreed, but did not have a persuasive alternative. The air force still wanted more money for the stealthy F-35 and a new stealth bomber. This despite the fact that other nations were developing more and more sensors that could nullify stealth.
The air force has been in this positon before. This was seen during the 1960s when the air force and navy aviation suffered unexpectedly high aircraft losses because their aircraft and pilots were not prepared for the lower tech Russian aircraft used against them over Vietnam. This led aircraft to be again equipped with cannon because the new air-to-air missiles were not yet reliable enough to replace the “old fashioned” cannon.
Then came the concept of using your own aircraft for "aggressor (or dissimilar) training." This began in the 1969, when the U.S. Navy established the original "Top Gun" fighter pilot school. This was done in response to the poor performance of its pilots against North Vietnamese pilots flying Russian fighters. What made the Top Gun operation different was that the training emphasized how the enemy aircraft and pilots operated. This was called "dissimilar training". In the past, American pilots practiced against American pilots, with everyone flying American aircraft and using American tactics. It worked in World War II, because the enemy pilots were not getting a lot of practice and were using similar aircraft and tactics anyway. Most importantly, there was a lot of aerial combat going on, providing ample opportunity for on- the- job training. Not so in Vietnam, where the quite different Russian trained North Vietnamese were giving U.S. aviators an awful time. The four week Top Gun program solved the problem. The air force followed shortly with its Red Flag school. In the early 1980s, the Russians established a dissimilar air combat school, and the Chinese followed in 1987.
The air force has another persistent problem that has not yet found a solution. This goes back a century, to when aircraft first became a factor in military affairs as they demonstrated their superior ability to see what the enemy was up. Most of the use of air power at the beginning was about reconnaissance, and preventing the enemy from seeing what you were doing. Between the world wars, the idea of using air power as an offensive weapon developed. This proved to be more of a factor at sea, than on land, where the reconnaissance was still the most useful service air forces provided. Strategic bombing was greatly misunderstood by air forces during, and after, World War II. Tactical bombing (and strafing) was more useful, because the fighter-bombers were providing reconnaissance at the same time they were attacking the enemy who were in the way of friendly ground troops.
The U.S. Air Force, however, was not a big fan of "tac air" (tactical air power), because they believed they could be more decisive with strategic bombing. The problem with World War II strategic bombing was that strategic bombing was a blunt instrument. A lot of damage was inflicted, but it was, for all practical purposes, random. So while millions of German and Japanese workers were diverted (because they were dead, or had to deal with damage to homes and businesses) from the war effort by the bombing, there was no decisive effect, as the air force generals intended.
So after a century of trying the ground forces (and non-aviation naval forces) still cannot get the people up there to come down and get a much needed reality check.