Determining sub/ship/helo without video:
All unknown helicopters and subs are hostile. Any unknown ships with unknown airborne craft departing it are hostile as well. this does not apply for unknown ground targets unless the aircraft is hostile or a missile.
Carrier:
Always keep your carrier loaded with planes. Alert 5 works well with this. The planes go on deck but do not launch until the order is given. These fighters can destroy anything when ready.
HARM missiles:
When attacking an enemy ship, use a plane armed with HARM missiles. They disable the capability for the ship to send return fire.