Per the Manual:
Air units within 8 hexes, or fewer if their range is shorter, of an enemy port that have remaining operation points
at the end of their turn might intercept and attack the supply convoy of an enemy and reduce its stockpile for the port. The air unit must be in support mode and have naval attack mission selected. They will still be able perform all actions available on the enemy turn.
So does this mean that an air unit can interdict two naval unit moves AND then also perform do supply convoy attack.
Also page 80 of the manual, under submarines specifically says, "Carrier fleets and air units may always attack submarine fleets."
carrier fleet may attack a submarine as if it was an air unit. When a carrier fleet attacks a submarine it uses 25% of its naval air power. ---- page 98
