The super carrier has two problems in the 21st century: 1. they are incredibly expensive to build and operate, 2. technology has moved on and carriers are increasingly vulnerable to a host of threats.
Threats to Super Aircraft Carriers
Two newish threats really stand out against carriers: Hyper-sonic carrier killer missiles and submarines. These greatly reduce our carriers effectiveness against Super Powers like China and Great Powers like Russia although carriers are still massively effective against smaller maritime countries.
Of course even super carriers are vulnerable against old fashioned tactics: if an enemy can attack with enough aircraft, cruise missiles and super sonic anti-ship missiles all in the air at the same time, defenses will get overwhelmed and something is bound to get through. Remember, even though super carriers are massive and very hard to sink, all an enemy has to do is put the flight deck out of action to render the ship operationally useless. Not many countries can put together such an attack but two that have the resources are, again, China and Russia.
Submarines are not new, but submarines good enough to slip past our escourt screen are new. Submarine technology has advanced a lot in the last 20 years, torpedo and sub launched anti-ship missile tech has grown too. And the numbers of good modern submarines in the hands of our rivals has gone up dramatically. Numbers count. We might be able to defend against simultaneous attacks by 3 submarines, but what if they have 5?
Lastly, we have costs. A super carrier has thousands of highly trained, highly paid, crew onboard. You have to pay, feed, clothe each one. Moreover, a carrier cannot operate alone, it needs a battle group, a mini-fleet, of escort vessels to guard it and supply ships are needed to fuel and rearm the smaller escorts. So for every carrier you have to build, man and maintain a small fleet. And THEN you have to build some extras for replacing war losses. There is a real question as to how long America can continue to pay these enormous sums of money just to keep super carriers operational.
The Future: Drones and Submarines
These are largely my predictions based on current trends.
We will slowly see more combat drone aircraft introduced to the US Navy. First on aircraft carriers for high risk missions, but also on amphibious assault ships that have flight decks. Drones require fewer people to maintain them so we may see a new class of carrier emerge, one with a few manned fighters for air to air defense and attack drones for bombing missions.
Submarines: The US has great attack (hunter/killer) submarines. But again, they are so advanced, so expensive to build that our enemies can afford to out-class us with shear numbers. We need some cheaper nuclear attack submarines and frankly we need some conventionally powered subs for coastal defense if nothing else.
I’m not sure how to do it but there must be a way to cut costs on building a nuclear attack sub. Perhaps designing it to do nothing but hunt and kill other submarines and merchant shipping? We need to come up with a class of these.
Conventional subs: these are very quiet, very hard to detect when they are lurking. They are cheap compared to nuclear subs and many surface ships. They can be very useful in guarding coasts and ports against enemy submarines. Many other navies have them and it would serve us well to have first hand experience of their strengths and weaknesses. Germany, Japan and the Netherlands all make really good conventional submarines, we should select something off the self and buy them for defense of port duties.
Don’t think I am anti-carrier or anti navy. The US Navy, combined with the US Marine Corps remains the most effective way for America to project power world wide. I’m just trying to identify upcoming trends.