Naval Fleets

Are naval Fleets used in war still and if so what is the strategy behind them and how do people use them.

Sub nukes are the only nukes that can be quality upgraded.
Navy fighters are pretty good against interceptors.
Guided missiles and ship based cruise are really effective

But you must have a strong economy, because the navy is expensive.

It also is a “Cadillac� means reaching across the seas. No having to capture local C3 first.