Carrier Strike Expansion Disk contains an update to v1.1 of the base game, which includes several incremental changes to the game engine, a change that increases attrition, five new (hypothetical) scenarios and one new campaign.
The scenarios are as follows:
1) Wake Island (Dec '41)
2) Plan Orange (Jan '42)
3) Rossel Island (Mar '42)
4) Guadalcanal (Aug '42)
5) Operation KE (Feb '43)
Any of these scenarios may be used as starting points for campaigns.
In addition, one new campaign has been added, 1947 Campaign, which postulates that war had been delayed by five years and includes weapon systems that were only in their infancy toward the end of WW2, such as night fighters and bombers, as well as first-generation stand-off weapons.