Players have noticed that the boats and zeppelins to Northrend in Wrath of the Lich King Classic are having issues, with players falling off boats/zeppelins or otherwise not zoning into Northrend properly.
To remedy that, Blizzard added a teleportation option to the Northrend Boat/Zeppelin Master NPCs, allowing you instant teleportation to Northrend. For example, Greeb Ramrocket, the Borean Tundra Zeppelin Master in Orgrimmar, will teleport you to Warsong Hold.