The aircraft carrier scene has heated up in the last 2 decades, following are the countries actively operating or planning to operate carriers.

Japan is converting its two Kaga class carriers
The US has 11 plus the Wasp and America class.
The Chinese have multiple carriers in service.
The UK has 2 in service, albiet barely used to full capability due to lack of own jets.
India has 2 and plans for more.
South Korea is planning to build dedicated carriers.

This article as a Video, do like, share and subscribe.
Aircraft Carrier is a generic term used for vessels that have expansive full length flight decks which can be used for co-ordinated and regular air operations of multiple types of aircraft.

These types of vessels were researched about and saw massive development in years leading upto WW2 and then after it. Currently, the navies around the world have settled on three types of basic design concepts.

CATOBAR: Catapult Assisted Take Off But Arrested Recovery eg. Nimitz class, Fujian class

These have angled landing area for 3-4 cables that aircraft hook onto while landing with their catapults mounted on the bow and end of the angled decks.

STOBAR: Short / Skijump Take Off But Arrested Recovery eg. INS Vikramaditya, INS Vikrant R11 (comm 2022) and Admiral Kuznetsov class

These also have angled decks but have a ski-jump which can be used by high thrust to weight aircraft to fly off of. They also have 3-4 cables for recovering aircraft.

STOVL: Short / Skijump Take Off Vertical Landing eg HMS Queen Elizabeth class, ITS Cavour

These might or might not have a ski-jump but always lack angled decks (except conversions eg ex-INS Viraat) and no cables for jets to hook onto.

In WW2, the primary aircraft were torpedoe carriers and dive bombers. This meant aircraft had to be in visual range to use these weapons, well within the range of anti-aircraft guns on the ships.

This, with circling combat air patrol over the enemy fleets meant large formations of fighters, torpedo carriers and dive bombers had to be sent to ensure hits. This has now wildly changed due anti-ship missiles which can be launched from beyond visual range.

Ships these days have surface to air missiles and powerful radars to snuffout enemy aircraft at long ranges.

What hasnt changed at all is that all naval think tanks agree that whoever detects the enemy first gets a better chance of scoring first hits.This puts a lot of weight in detection and counter detection working to identify the entire fleet and its weaknesses.

Also, what hasnt changed is basics of fleet tactics. If you have more than 1 carrier, the Imperial Japanese liked to keep them together which had the following pros and cons. The Americans like to keep them separate which also has its own pros and cons listed below.

American Tactics

Pros

Difficult to ascertain location of their entire fleet in one go.
Larger overall footprint so attacking forces need to be vary of surprise attacks or counter attacks means less mass committed to first wave.

Cons

Need radio communications to co-ordinate ops so no radio silence or send piece meal waves.
Needs experience and training to bring both air groups on the target at the same time.
More ships needed for escort and resupply.

Imperial Japanese Tactics

Pros

Radio silent ops are easier
Fewer ships required for escort and resupply.

Cons

Detection means entire fleet is found, so all cards are visible at first contact.
Concentrated mass also means sensors have more emissions to detect (for eg sound)

The Role of Aircraft

Presence of a mobile fleet of aircraft that can cover 1000s of nautical miles in a day makes them a great asset and deterrent. Aircraft can help in both detection and destruction of naval targets by covering vast swathes of ocean quickly.

Let us dive deep into how naval aircraft help with detection, destruction and defense in 21st century. The roles below are primarily for naval jet fighters like F-35C, F-35B, J-15, MiG-29K and Su-33.

Detection

Imagine a naval vessel that has powerful radars that can detect a fighter sized target at 200 km, that is great, right? It just means that at 200km the returns from the target are strong enough for the sensors on the vessels to detect the fighter.

The emissions however can be detected at ranges far beyond the ones strong enough to register on the side of the emitter. It means that a fighter flying with no emissions at 250 km might still detect the ship but the ship might not see the jet.

Modern radar warning receivers can even warn if the returns are strong enough for detection or if there is a radar lock.

Plus friendly naval vessels are also limited by radar horizon so it will be difficult for them to look for anything very low but far away.

Aircraft can fly high and carefuly navigate around targets to maintain contact while not being detected.

This means, a jet fighter can only use its Radar Warning Receiver and other passive sensors looking for targets beyond visual range without emitting radio energy.

Given the speed and sensitivity of modern systems, it is easy peasy to cover massive areas in a single sortie. Multiply it with a combat spread of 1,800 m / 1 nm separation and you can triangulate target position based on radio energy.

A surface vessel needs hours to get out of detection range or below sea level radar horizon. A jet fighter can do it in seconds if not minutes.

If chances of detection are high, they can just dip below the radar horizon of the enemy vessel and hide using the Earth’s curvature. See the picture below to visualize what I mean.

These detection capabilities can also be used for battle damage assessment. I mean if the target keeps emitting after the time of arrival of missiles, it wasnt hit and is healthy to fight.

Hence surface vessels are always in a jeopardy, do they emit with their radars to build an image and let themselves be tracked passively.

Or do they maintain strict emcon as in emission control and increase risk of hits and thus battle damage. It comes down to training, tactics plus threat levels matrix developed by the operating navy.

Destruction

This part is tough because you need to plan according to the enemy, its radar systems, its air defenses and the operating conditions. It is called mission packaging where you define each parameter to help you get the best outcome.

Most modern naval fighters have some or the other primary anti-ship missile so choosing the weapon is the easy part. Choosing how many and how to use them is difficult.

But aircraft are infinitely flexible platforms compared to a naval vessel. A naval vessel needs hours and days to get into position, compared to hours and minutes for an aircraft.

So you can use an aircraft as a spotter for naval platforms that are within missile range but outside strike back range.

For eg. a Tomahawk missile can hit targets 1,500 km away, if your enemy cannot detect you at that distance, you can position a ship to launch the missile and a jet serves as a spotter by checking the emissions.

They can also act as escorts providing jamming support to avoid unwanted detection while enroute.

For aircraft launched missiles, it is more difficult but less risky. An aircraft can duck beneath the radar horizon and launch missiles very close to the target ensuring late detection of the platform and the missile.

Going up against an enemy carrier is obviously very difficult and a whole different ball game. We will discuss it in the next section.

Air Defense

Aircraft have their own radars and missiles for self defense and offense against other air assets. This helps a lot and I mean infinitely more against modern sea skimming missiles.

Since jet fighters fly high, their radar horizons at surface are much farther than a surface vessel. This means they can sea skimming missiles flying in below with look down capabilities.

With their onboard missiles, they can target the missiles while also alerting their mothership about the attack. More jets can then be launched to intercept incoming salvos and reduce the load on individual ships.

Or else, data linked targetting like US Navy’s NIFC-CA can be used to use ship board missiles to target threats beyond the range of ship borne sensors.

It is also a difficult thing to master though, US Navy with its carrier based tankers and long ranged F-14s had trouble maintaining a 400 nm bubble to keep out Soviet bombers attempting saturation attacks.

It comes down to using limited range of aircraft as efficiently as possible to counter as many threats as possible.
Graphic via Maritime Warfare in a Mature Precision-Strike Regime by Andrew F. Krepinevich, CSBA, 2014

Aircraft Carrier vs Aircraft Carrier

With the three primary roles of carrier fixed wing aviation defined, let us take on the elephant in the room. How do carriers fight each other? Time and again, it has been said that the carrier that detects first, shoots first and kills first.

That means fighters have to be used for detection work. Usually fighters with a longer range will have an upper hand as they can cover larger areas or keep their mothership farther away.

Carrier based aerial refueling like buddy tankers can also help increase this range further.

Non-carrier surface vessels thus face a unique challenge, use radars to detect and give away your location or keep quiet and let the aviation do its job.

Planning attacks is very difficult though. You need to keep an eye on all aspects of the enemy CBG, as in its submarines, its surface vessels and their onboard capabilities.

The comes the important task of gauging how they are employing their own air wing and find a way in to launch your missiles.

You need to evade enemy combat air patrol to get in range for missile launch. These are very complex decisions for mission planners and it needs to be done quickly before the other party detects you or attacks you. There are more questions which are even difficult to answer.