Terror Mail

Air Mail was a message service used by the Hairy Hooligans of Berk and the Dragon Hunters.

In Defenders of Berk
It was first tested by Hiccup Haddock III and Fishlegs Ingerman using Terrible Terrors. Hiccup used Sharpshot as it's first courier to notify Fishlegs of the Screaming Death and it's sinking of island in it's search for it's mother.