We weren't "attacked" unless you count the falling flak that was being shot at "whatever" it was that night. As for a coverup? It was spread all
across the news the next day, so I'm not sure what was covered up?
from: www.laalmanac.com...
Battle of Los Angeles, 1942
In the very early morning hours of February 25, 1942, Angelenos were jolted out of bed by screaming air raid sirens and thundering anti-aircraft gunfire. Hundreds of thousands of residents, ignoring blackout rules, snapped on lights and spilled into the streets to watch sweeping searchlights and orange tracer shells streaming into the night sky. Thousands of volunteer air raid wardens grabbed helmets and boots to rush into action.