Congruent carrier development from shared aims

Archival records from British future-building committees sit alongside parallel American and Japanese work. Designers gathered information broadly instead of treating national experience as self-contained. Congruent development best describes the resulting similarity: the navies shared some aims and evidence but did not arrive at identical answers. Their carriers could resemble two sides of the same coin while retaining distinct balances of armour, aircraft capacity, and operating method. The distinction cautions against attributing every shared feature to direct copying.