Before daybreak Spruance had suggested sending bombers to crater the airfields on Rota and Guam, but the contact-fused ordnance was largely used up, and Mitscher hoped to use the armour-piercing ordnance on the Japanese fleet.
Before daybreak Spruance suggested if the daybreak searches revealed no targets the bombers could be sent to crater the airfields on Rota and Guam. With the fleet's contact-fused ordnance largely used up, Mitscher was left with the armour-piercing ordnance which he needed to combat the Japanese fleet.