How Does Airpower Work in CWC?

[Mako]

I read about airpower in CWC on another forum, and they mentioned the Soviets had achieved "air superiority" in a battle report for a game, so I am curious about how aircraft work in the rules, e.g. a once a game die roll for support, points allocations to buy it, turn-based, pre-planned sorties, opposed die rolls every turn for support, etc.?

Are there different types of aircraft support in the game too, e.g. fighter cover, ground attack aircraft, attack helos, planned arrival times or random turn entries, possible delays in arrival, etc.?

[Leon]

The Air Superiority is rolled for at the start of the game and the outcome decides who can do certain things:

"AIR SUPERIORITY
The side that controls the skies holds the advantage when it comes to combined-arms warfare. To determine Air Superiority both sides should each roll a single die before the game and apply the Air Superiority modifier from the relevant army list to the score. Some lists state that there is no possibility of gaining air superiority, in which case, skip the test. Compare the two die rolls."

The die scores can give results of either Contested / Partial / Full superiority and these affect your command value when trying to call in air support.  If you've got Partial or Full you also gain better protection against your opponents air support attacks.

Attack themselves are either scheduled or called in, and you can choose to use fighters, bombers, helos, etc as long as you've got them in your army.

[Big Insect]

Are there different types of aircraft support in the game too, e.g. fighter cover, ground attack aircraft, attack helos, planned arrival times or random turn entries, possible delays in arrival, etc.?

'Air Power' is represented by Ground Attack aircraft (AIR:GA), Bombers (AIR:BM) and Transport aircraft (AIR:TRANS by both Attack Helicopters (HELI:ATTK) and Transport Helicopters (HELI:TRANS). Fighters can often be used for ground attack, and are represented in the AIR:GA category. As CWC is a table-top ground based set of rules there is no Fighter on Fighter combat (or Fighter on Bomber) that is all dealt with in the Air Superiority rules, as outlined by Leon above.
Ground Attack and Bombers appear on-table briefly - either having been called in to strike a pre-selected target (a scheduled strike) or being called in by a friendly on-the-ground FAC (Forward Air Controller).

Helicopters and Transport planes can also be brought on table as part of a scheduled strike or a paratroop drop or a to drop off ground troops, or they can operate on-table - in a similar way to a flying AFV or Transport vehicle.
So lots of options. However, unlike WW2 for example, airpower is much less of a game decider in CWC, unless all opposing AA (anti-aircraft weapons) and enemy air has already been dealt with. As we saw in both Gulf Wars and now in Ukraine - flying above a 'modern' battlefield is an extremely dangerous business and this is reflected in the impact that air-attacks have on ground units.

Helicopters, if used carefully and in a coordinated manner with friendly ground troops, can be highly effective, but they are generally (relatively) few in number and extremely vulnerable to enemy AA ground fire and even enemy ATGWs.
There is a comprehensive section in the rules on helicopters and air-attacks in general.

I hope that helps answer part of your question 

[Mako]

Thank you for the detailed information and replies. I really appreciate it.