The United Kingdom views its investment in maritime airpower as an important part of its contributions to the NATO Alliance. In 2020, it committed the CSG to the NATO Readiness Initiative, alongside other inputs such as the British Army's leadership of the NATO Enhanced Forward Presence in Estonia. Reflecting its historical areas of strength, the United Kingdom also hosts Allied Maritime Command (MARCOM) in Northwood, England, and the RN regularly contributes to the Standing NATO Maritime Groups and Standing NATO Maritime Countermeasures Groups. The RAF is similarly active in supporting NATO exercises and air policing missions.
Rebuilding the capability to deploy a CSG with embarked F-35Bs and a mix of helicopters presents not only the United Kingdom, but also NATO, with a new range of tactical options. This includes the added operational flexibility that comes with increased capacity (or 'mass') and new ways of bolstering the NATO Alliance's conventional deterrence and defence posture.
This enhancement in European NATO Allies' contributions to NATO maritime airpower—alongside the smaller and older carriers operated by France, Italy, and Spain—comes at a time when the U.S. Navy's own (much larger) fleet of aircraft carriers is facing growing demands from other theatres. Most notably, the U.S. military is increasingly having to juggle its ongoing presence and commitments in Europe with efforts to deter China's fast-growing People's Liberation Army, Navy, and Air Force in the Western Pacific. The return to United Kingdom carrier operations therefore presents opportunities for the RN and RAF to 'take some of the slack' from their U.S. counterparts, either by deploying the CSG within Europe or by taking up station elsewhere—for example, in waters off the Middle East—to help free up a U.S. task group for operations in other parts of the world.
It also comes as Russia continues to develop and deploy capabilities intended to deny NATO access to waters and airspace off Norway in the event of a conflict (so-called 'anti-access, area denial'), securing Russia's northern bastion and approaches and making any Allied reinforcement of Norway a more complicated and risky undertaking. Russia's naval and air forces similarly hope to contest NATO's access and control as far as the Greenland-Iceland-UK gap, directly threatening the SLOCs of the North Atlantic that lie beyond. These waters are vital to NATO's broader strategy and resilience, enabling the safe and timely movement of troops and materiel from North America to reinforce the European theatre in the event of a crisis or full-blown conflict.
With that in mind, here is a recording of the late Professor Eric Grove giving a talk at the International Institute of Strategic Studies regarding NATO naval planning in the 1980s - and the similarities to the situation today.
Professor Grove mentions carriers a lot, in terms of protecting both shipping and amphibious forces.
At 50:15 he suggests that the thing hostile submarine captains dread most of all is the dipping sonar - and that an airborne radar flooding an area will keep the hostile submarines down. He then describes witnessing an ASW exercise in which a number of NATO submarines transmitted Soviet levels of noise, and everyone was covered by either an ASW helicopter or an MPA. Carrierborne fighters are also mentioned.