Airship
Airship is an Adventure Map object that allows heroes to fly over land tiles, water tiles, and obstacles. Boarding or disembarking from an airship takes the remainder of a hero's movement allowance for the current day. It prohibits a hero to interact with objects, other friendly heroes or attack enemies, but other heroes (both allies and enemies) can interact with or attack airship respectively, even if an opposite hero is on a boat. Heroes can disembark from an airship or make a stop only on unblocked land tiles. An Airship can carry only one hero and their army at a time.
Airships can be purchased from an Airship Yard for 5000 
and 20 
, or obtained on the adventure map. If a hero on an airship is defeated in a combat, the airship disappears.
Airships can be entered even if they stand on water, as long as they're on the shore.
Mentions
In World on Fire, the airship is implied to have been created from a stolen Bracadan skyship.