How would the Navy justify an interwar catapult carrier?

How could an interwar designer justify fitting a carrier with catapults?

By showing that catapults launch heavier aircraft; the harder argument would be adopting steam rather than hydraulic machinery.

The operational argument for a catapult is straightforward: it lets the carrier launch heavier aircraft than deck run alone permits. Navies were already moving toward catapult-equipped ships late in the interwar period while also changing arresting-wire arrangements. The difficult choice is whether to move from familiar hydraulic equipment to steam. British concern about routing steam around the ship would make that later transition the harder institutional sell.