Once you have destroyed the three ships, go up as high as you can. Then, dive while shooting unguided missiles at the planes. When you first start the mission, you will launch off an aircraft carrier. The message "We've spotted three enemy ships coming this way! Defend the carrier" will appear. Destroy the three enemy ships. You will then be asked to take out the radar guns before going after the base. There are five of them. When destroying the planes at the base, go as high as you can above the base then dive toward it at medium speed. When you get close enough, shoot unguided missiles to destroy the planes.