Would Italian carriers change British planning?

Would converting Francesco Caracciolo and building Italian carriers have prevented the Taranto raid?

Not automatically: carriers in port might lack aircraft and night capability, while Italian and German carrier programs would probably have triggered additional Royal Navy carrier procurement.

Treaty tonnage could have supported two Italian carrier conversions on roughly 30,000-ton Francesco Caracciolo hulls. A carrier alongside in port would not necessarily embark ready aircraft, generate wind over the deck, or stop a night strike without funded night-flying capability. Italian carriers would also alter British threat assessments and likely increase Royal Navy carrier demands; Hitler might respond by insisting on a German carrier. The example shows why alternate-history changes cannot be assessed in isolation.