Why a carrier should rely on escort missiles

Should Queen Elizabeth carry Sea Ceptor or similar air-defence missiles?

No. Escorts should provide the missile layers because carrier VLS launches would interfere with the flight deck and the carrier is not meant to operate alone.

A vertical CAMM launch from Queen Elizabeth could scatter foreign-object debris over the flight deck. Clearing that hazard would interrupt the aircraft operation that gives the carrier its value. The preferred defense begins with F-35Bs, followed by Type 45 Aster missiles, frigate Sea Ceptor, close-in weapons, chaff, and other decoys. Because the carrier should deploy with escorts, its own space and weight are better devoted to aviation than to duplicating the outer missile screen.