Col Tibbetts & co pretty much ended the war in Japan singlehandedly with air power, but I doubt (hope that we won't) see that again.
W
estmoreland proved the fallacy of that notion.
As did the British at the Somme.
It is all about destroying the Enemy forces ability and desire to fight by killing them at the least cost to your own side. Once the Bad Guys understand there is no hope or are killed then perhaps they will see the light and quit the field and go back to the farm.
And that is getting at the heart of the situation. It is a function of several variables and air power is a tool in the toolbox.
How effective it is is dependent on the aim, the opponent, what amount of "air power" you have, and are you prepared to use it and accept the consequences.
At the end of the day the basic calculus of war and human nature hasn't changed. Its all about a cost benefit analysis for the enemy. If there's no hope of achieving their aims, then they won't attack, or fight.
This has been shown on human and animal terms, take away all hope and species tend to curl up and give up. When extrapolated to state systems, that turns into finding another way to achieve your goals.