@WTFPurpleAlpaca @Terry Close encounters aren't common occurrences with these types of vessels.
You engage from many miles away, your targets often beyond the horizon.

As for countering small air units, many ships are already equipped for that (pic related).
While many corvette class ships opt for a small cannon on the front (previous post shows those), others are fitted with an AA 20mm Vulcan cannon.

These things are more than a match for swarms of drones.
Accurate, fast, and fully automated.
A cloud of led at a press of a button.
Vulcan cannons are wild.

@WTFPurpleAlpaca @Terry It's was always a game of logistics.

I haven't heard of flying drones taking out ships yet though.

A couple of ships were downed by naval drones.
Basically remote controlled torpedoes.

Swarms could be useful against older models of ships that have exposed munitions.
Like missile ships with launchers on deck, or destroyers with torpedoes on deck.

Flying swarms don't carry enough of a punch.
I'll remind you that Kamikaze planes, crashing into ships, did basically no damage to their targets, and proved an inefficient strategy.

The average ship's hull is steel on the bottom, and aluminum up top.
Neither layer is thin, thicker in some parts, angled where possible, and with a few redundancies.