That's not their main job, though. With all due respect, it's laughable to maintain that this is why we maintain the world's largest carrier fleet.
The main job of aircraft carriers is to go forth and kick ass. I didn't need to "research" this: it's common knowledge. But here you go, from the 2010 NOC:
"Aircraft Carriers
Nuclear-powered aircraft carriers (CVNs) and their embarked air wings provide responsive, flexible, sustainable strike capability and capacity that does not require diplomatic access. Aircraft carriers serve as the centerpiece of carrier strike groups (CSGs) during power projection operations. In the event of conflict, multiple CSGs can aggregate, along
with other surge forces if required, to form an expeditionary strike force capable of projecting significant power at-sea and ashore.
The standard CSG force package includes a CVN, air wing, up to five surface combatants, a direct support submarine, and a combat logistics force ship. The ships provide integrated air and missile defense (IAMD) to include ballistic missile defense; and strike warfare, undersea warfare,
surface warfare, maritime security, and sustainment. When not conducting coordinated operations, these ships will often disaggregate to conduct dispersed security cooperation, counter-piracy, counter-terrorism or other maritime security operations in the theater."
It's all about combat, providing "responsive, flexible, sustainable strike capability and capacity that does not require diplomatic access." Humanitarian missions are part of US naval doctrine, but it's not why we have 11 aircraft carriers.