flight has 6 distinct synonyms spread across 5 of its 12 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a stairway (set of steps) between one floor or landing and the next
an air force unit smaller than a squadron
passing above and beyond ordinary bounds
“a flight of fancy”
the path followed by an object moving through space
a scheduled trip by plane between designated airports
“I took the noon flight to Chicago”
Synonyms, antonyms and the broader and narrower relations for flight come from Princeton University’s WordNet. Full sources and licences.