From Longman Dictionary of Contemporary Englishvapour trailˈvapour trail British English, vapor trail American English noun [countable] TTAthe white line that is left in the sky by a plane
Examples from the Corpus
vapour trail• It was leaving an impressive vapour trail.• High overhead, a jet laid its vapour trail across a bleached-blue sky.• Ruth flopped back in the lounger and studied the vapour trail through half-closed eyes. 