Let us call a spade a spade shall we?
Can anyone challenge USAF?
If we take divine intervention out of the equation then not a chance in hell...not in the foreseeable future!
China will be their major rival in the future but currently we cannot compare USAF to anyone.
The US military machine as a whole is extremely powerful, to say that only their air force is dominating is an understatement that perhaps reflects lack of knowledge or something else...
They have seen more action in modern warfare than any other of their rivals, their joint operations have ensured that all of their arms are primed for complete land, air and sea dominance.
They use the best weapons and technology, have devised hell of a lot of tactics and are excellent professionals in all military arms.
In terms of combat readiness and projection of strength, they are unmatched by any other power currently.
You want to see professionalism then see how they are always geared up and alert when on patrols despite the intense heat or whatever the conditions are, i once saw a video of an Afghan airport where the US Infantrymen on guard detail were standing alert on the tarmac (which must have been boiling going by how the sun was blazing) fully geared up!
This is called discipline and not cowardice, this is why the professional soldiers inflict much more punishment on their enemies...because they are prepared!
Their rifle firing discipline is very good and reflects a well drilled and well trained professional army, compare that to the recent action by Afghan Army (quoting them because Afghans are natural warriors) many of whom even in the current scenario are firing from the hip without aiming when they are under fire...this is not professionalism and leads to unnecessary casualties and wastage of ammo.
Many things the ordinary person flaunts as cowardice or being over cautious is actually the right way of doing things...
Like or dislike of US policies or decisions does not mean that we do not acknowledge the facts.
Our interaction with US military professionals in the past and present has been very fruitful and is always a good learning experience in terms of sharing various tactics and strategies.