Courageous and Glorious retained a doctrinally obsolete deck

The lower flying-off deck promised rapid fighter launches while aircraft landed on the main deck. Without radar, however, fighters launched only after visual contact would arrive too late, and Royal Navy doctrine was already moving toward continuous patrols and sustained operations. The opening consumed hangar volume, shortened the useful flight deck, and placed guns where they disturbed takeoff airflow. Courageous and Glorious also stopped roughly 2,400 tons below the treaty ceiling, leaving displacement that could have bought protection, aircraft, weapons, and future growth. Their all-turbine plant still delivered about 6,630 nautical miles at 10 knots, undermining the idea that long range required Béarn's mixed machinery.