In AAA, if you are defending against a sea attack, and you are defending with an aircraft carrier, do the airplanes on the carrier contribute to the battle or are they considered cargo? The rulebook doesn't seem to define a specific rule for this scenario.
The air units that are on an aircraft carrier participate in the defense, they are not considered cargo. On page 20 of the rulebook under Order of Play.
And in the Appendix (page 30) under Aircraft Carrier, or (page 27) under Fighter the example image.
and from the online FAQ:
Depends on your version. I am playing the 1941 version where the rulebook has 31 numbered pages not including the back cover. There is a misprint on page 13 in the illustration showing where a tank can and cannot blitz (The tank cannot blitz in either illustration as there is an industrial complex preventing blitz).
On this page, (p.13), under "Aircraft Carriers: "...Fighters belonging to a friendly power on board another power's carrier (guest fighters) must remain on board as cargo in the carrier moves in this phase. (Combat Movement) They cannot take part in combat and are destroyed if the carrier is destroyed."
That seems to refer only to attacking, as on page 26, under "Aircraft Carriers" it states: "...Fighter Defense: Whenever a carrier is attacked, its fighters (even those belonging to friendly powers) are considered to be defending in the air and fight normally..."
So there you have it: All fighters on aircraft carriers DEFEND but only fighters which belong to the same power as the aircraft carrier may ATTACK.
You could also choose to have the fighters fly to another battle or location away from the battle and return to the aircraft carrier (if it is still there!) after battle resolves.