I see, I just hear a lot about how China can make it too expensive for US to mount an attack.
Being able to send j20s to take down high value targets is just as important as good defence.
In terms of a large scale, strategic air war, there are a number of aims that each side would like to preferably achieve in terms of their ability to destroy opposing combat effectiveness.
From "most preferable" to "least preferable," it may look something like this:
1: destroy, deny or disrupt the opfor from deploying their aviation assets at the staging areas from which they will be based to conduct their missions
2: destroy, deny or disrupt the opfor the ability to generate effective sorties (in both quality and quantity) from their staging areas (i.e.: the opfor have already deployed their assets to the staging are)
3: destroy, deny or disrupt the opfor's aviation capability to conduct their mission
before they reach the "area of operation" in the air (i.e.: payload deployment range)
4: destroy, deny or disrupt the opfor's aviation capability from conducting their mission/deploying their payloads once they are in the "area of operation"
5: destroy, deny or disrupt the opfor's payload from reaching their target after the payload has been launched
Those numbers form a "layered" air war concept, where the overall goal is to deny the enemy the ability to attack your own targets while maximizing the ability for you to attack the enemy's targets.
There's been a quote long passed around, that goes something like this "the best place to destroy an enemy fighter is when it is on the ground".
In terms of hardware, the assets required for each of the points may be as follows:
1: ability to contest air superiority at long range to enable robust ISR capability, to enable robust EW capability, and to enable long range strike weapons (missiles, bombers -- although some long range strike capability in terms of IRBMs, LACMs and stand off range missiles may not require as robust of air superiority)
2: similar to 1, but would occur at a later "stage" of a conflict when the opponent had already managed to deploy aviation assets to their staging area
3: long range air superiority fighters, force multipliers (AEW&C, EW, tankers) -- basically contesting air superiority
4: similar to 3, but closer in geographic proximity to your target that you are trying to defend -- will likely involve shorter range fighters and be less dependent on tankers, and may also involve long range SAMs + land based early warning sensors + airborne early warning sensors + defensive EW
5: a combination of long range SAMs + short range SAMs + point defense weapons/C-RAM like systems + decoys + short range fighters + defensive EW
In terms of cost, the hardware and training that is required for 1, 2, 3, 4, 5 -- doing only 5 is the cheapest, whereas doing 1 is the most expensive.
Most nations might only have the funds to achieve only point 5 and point 4, whereas some nations might have a capability to do 1, 2, 3, 4, and 5 but on smaller scale (for example, involving 100 fighters instead of 1000), whereas a few nations may have the funds to do 1, 2, 3, 4, 5 in very high tech, truly strategic scale operations that involve thousands of combat aircraft, dozens or hundreds of force multiplier aircraft, hundreds or thousands of long range missiles etc.
