Why carriers still change Force Z despite uncertainty

Could Courageous and Glorious survive yet still make little difference to the wider war?

The final scale is uncertain, but a carrier with Force Z clearly adds fighters, radar, escorts, and strikes on Japanese landing shipping that change the operational problem.

The precise size of the counterfactual effect cannot be calculated with confidence. The narrower operational difference is clearer: a carrier gives Admiral Phillips fighters he knows are available, avoiding the historical ambiguity over messages about land-based air support. It also brings radar, fighter direction, escorts, and the ability to attack Japanese landing shipping before supplies are fully ashore. Those capabilities may not guarantee victory, but they slow the offensive, preserve choices, and give reinforced ground forces more time to respond.