Sky is related to Area. Area is related to State. State is related to Exist. 
Cruise is a synonym of Ease. Ease is the opposite of Difficulty. Difficulty is related to Level. Level is related to Orientation. 
Sky <--RelatedTo--> Area <--RelatedTo--> State <--RelatedTo--> Exist 
Cruise <--Synonym--> Ease <--Antonym--> Difficulty <--RelatedTo--> Level <--RelatedTo--> Orientation 