I'm not sure we're on the same page. I'm talking about A2/AD against the aircraft carrier itself, not the deployed aircraft.
Iran has been able to fire multiple shots at USS Lincoln whenever it got closer than 700 km to our shores, and it forced it to retreat and stay out of our firing range.
Now consider a country like China with supersonic cruise missiles traveling at Mach 3-4 in large numbers. They have the A2/AD capability to keep the USN at 3,000 km far from their shores. That renders a US aircraft carrier obsolete.