Re: A is actually not a bad piece of kit
(Quite apart from the fact that any reasonably up-to-date enemy would sink an attacking carrier in about five minutes using hypersonic missiles).
This is why your carriers need:
1 large, long-range, supersonic, interceptors carrying long-range missiles: to kill missile-carrying aircraft or inbound missiles a long, long, long way out. Pity that there aren't any more F-14s carrying AIM-54s, isn't it? F-35s with AIM-120s just aren't the same. And the British carriers simply won't have enough F-35s to stop a mass attack, anyway. Depending on the range from base, Tu-22M Backfire maritime strike aircraft can carry one, two, or three hypersonic 200+ nautical range cruise missiles, each with a one ton HE or a nuclear warhead. Backfires usually operate in regimental strength, 21 to 27. That's 21 to 81 Mach 6 inbound vampires from 200-250 nautical miles range... AIM-120s have a max range of about 70 nautical miles, an effective range against cruise missile sized targets of under 50 nautical miles. That's less than 30 seconds flight time for a Mach 6 missile...
2 escort ships with long range hypersonic surface-to-air missiles. The USN has lots of Ticonderoga and Arleigh Burke ships with Standards, max range 100 nautical miles, effective range against cruise missile sized targets 70-80 nautical miles. Anything that got past the USN's F-18s and F-35s armed with AIM-120s would have to get past lots and lots and lots of Standards; a typical USN carrier task force would have a Tico or a Burke as the goalkeeper, right next to the carrier, with 122 (Tico) or 90 (Burke) Standards, and would have one to three more Ticos or Burkes in the inner, Anti-Air Warfare, ring. (The middle, Anti-Submarine Warfare ring, would have ASW ships which would be nearly helpless against inbound hypersonic missiles, but the Russkies or the Chinese ain't gonna waste carrier-killers on ASW frigates. The outer ring would be mostly ASW helicopters, some of which might turn on radar enhancement systems to try to look like a carrier to a cruise missile's radar.) The RN has Type 45s, armed with Aster 15 missiles. Max range 30 km, or 16 nautical miles. Good luck with that.
3 local point defences. The USN's carriers have Sea Sparrow missiles, not much good against hypersonic cruise missiles but better than nothing, and Phalanx or Goalkeeper close-in defence guns, again better than nothing. (Note: the latest version of the Sea Sparrow has an effective range of about 12-15 nautical miles against cruise missile sized targets. That's right, the point defence system on American carriers is almost as long-ranged as the fleet anti-air warfare systems in the Royal Navy. Someone should tell the Admiralty that the days of 'give them a broadside and board them in the smoke' are long gone.) The RN might have Phalanx and a few 30-mm systems. Phalanx is a 20-mm Gatling gun, based on the Vulcan gun fitted to many American aircraft. Goalkeeper is a 30-mm Gatling gun, based on the gun carried by the A-10. The 30-mm gun the RN is getting is based on the Bushmaster revolver gun. I know which one I want on my ship when the signal 'Vampire! Vampire! Many inbounds, Mach 6, range 150!" goes out, and it ain't no bloody Bushmaster.
The RN's carriers ain't gonna last five minutes against a modern missile strike. The USN's carriers might actually survive one, maybe two, attacks... until the escorts run out of Standards. Then it's all over.