A fleet formation covered far more sea than the tightly grouped ships often shown on screen, making multiple visual lookout positions useful. In exercises, destroyers and airborne aircraft watched for approaching attackers and radioed the carrier to launch its fighters. A standing combat air patrol was possible, but short range, fuel use, and accumulated maintenance made continuous coverage costly.
Chapter · 10:07-12:18
Visual warning from destroyers and airborne lookouts
Before effective shipborne radar, dispersed destroyers and aircraft used visual spotting and radio reports to trigger fighter launches.