Fightercraft are necessary for any large ship. There have been quite a few real-life examples, such as the case of the Prince of Wales and the Repulse.
I wouldn't use that sea analogy really.
For one, the PoW and Repulse didn't have jump drives (the abillity to almost instantly jump to a friendly base).
Secondly, the were attacked by every fighter and bomber the japs had in the area. Which was a LOT. They still took quite a few fighters/bombers down and lasted surprisingly long, given the strength of the attack.
Either way, ships like the Aeolus are really effective agaisnt AI fighters. Not so much against human pilots, but then again, if you had human gunners on the Aeolus, it would be far more deadly too.
It depends on what is attacking you and in what numbers. But having a fighter cover is definetaly a GREAT boon to your defense.