Are aircraft skins restricted by game mode?
Some confirmed Deluxe aircraft skins are available in Online Mode immediately but require campaign completion before Campaign Mode use.
Confirmed explanation
The published cosmetic set names the F-4E Mobius and F/A-18C Team Zvezda skins. Their access rules are separate from the unlock rules for the underlying aircraft and from the preorder F-14A bonus.
What is not confirmed yet
Rules for every future skin, offline availability and account transfer have not been published.