The Lexingtons were laid down for battlecruiser operations and completed as aircraft carriers under the treaty system. Their original design belonged to a US Pacific-war concept rather than a plan to chase Royal Navy battlecruisers. Postwar budgets could reduce the number of capital ships ordered while competition among major navies continued as a qualitative race in speed, guns, protection, and prestige. The carrier conversion inherited a scouting-force mission developed for battlecruisers, which helps explain later choices that look awkward when judged as clean-sheet carrier design.
Chapter · 2:22-5:58
Treaty conversion preserves the Lexingtons' Pacific mission
The naval treaty converted the Lexingtons from battlecruisers to carriers while preserving the Pacific scouting and information mission that had shaped their original design.