Why an unaffordable peacetime refit could work in war

Was a full-length flight deck physically impossible on the Courageous class?

No. It required hull strengthening and was cost-prohibitive in peacetime, but wartime priorities could justify the work.

Engineering feasibility and procurement judgment led to different answers. The hull would need strengthening, which added weight, expense, and treaty complications when Britain was already building new carriers. Wartime removes the treaty objection and changes the value calculation because an existing flight deck can be returned to service faster than a new carrier can be built. Contemporary rejection of the project therefore does not mean the design could never have been executed.