As far as I'm aware, lights were used. I've seen map-makers add lights to stationary carriers, but it's impossible for moving ones. I've noticed a diamond-shaped structure on Japanese carriers under the main deck with 5 light sources. Maybe this was used to transmit info to the pilot (ie, too fast, too low, etc.)
Also, in the right conditions the wake might churn up some phosphorescent algae, leaving a long trail, lighting the way to the stern of the ship
