The War to End All Wars 3rd Ed.
Complete Game Rules
Phase 14: Air Guard
Air Guard is an option where you may deploy aircraft into sea zones, where they will stay until the start of your next game turn. In order for an aircraft to be able to do this it must firstly have enough fuel points to be able to fly into a sea zone and land into an adjacent territory (5 fuel points) and still have at least one fuel point remaining in order to participate in one round of combat, plus the aircraft can not have taken any actions earlier in the turn. While in the sea zone the aircraft may participate in any combats that arise from enemy ships entering the sea zone. These aircraft will then land during the Air Rebasing phase at the start of your next turn.