Aircraft vs. Submarine rules question

[crsluggo]

I apologize in advance if this question has been taken care of years ago.

So the rules state (pg.32) that: “…Submarines always fire in the opening fire step, whether on attack or defense. They can fire only on sea units. Casualties from this attack will be destroyed before they can return fire, unless an enemy destroyer is present. (Any sea or air unit can hit a submarine.)” (my emphasis added). Can I take this to mean that air units can attack subs without the need of destroyers? If so, isn’t this a step backwards in the A&A evolution considering the need for destroyers in Europe & Pacific to wrest control of the seas from the submarine menace?

[calvinhobbesliker]

No, you still need a destroyer. I think it’s it says that to contrast it with subs being unable to hit planes

[Krieghund]

Air units can hit subs in Revised without a friendly destroyer being present.  This requirement from AAE and AAP was dropped in Revised in the interest of simplifying unit interaction.  It was reintroduced in AA50, as removing it made subs too fragile.

[calvinhobbesliker]

Wow. This was in the revised forum. Sorry, I’m usually on either P40, AA50, or AA42, where what I say applies

[Krieghund]

No worries.  I’ve made that mistake myself on occassion.

[crsluggo]

Thanks Krieghund for yet another insightful answer.

[mozkaynak]

So, My understanding is that 
fighters and bombers can attack submarine by themselves and submarine can not fire back.
Please confirm that.
So how does submerging work here?

[Krieghund]

@mozkaynak:

So, My understanding is that  fighters and bombers can attack submarine by themselves and submarine can not fire back.
Please confirm that.

Correct.

@mozkaynak:

So how does submerging work here?

Subs may submerge at the end of any round of combat if there are no opposing destroyers in the battle at that point (as long as the battle is not over).  They have no effect on other units while submerged, and are ignored.  They resurface at the end of the noncombat movement phase, having no effect on enemy units in the sea zone at that point.