V-formation
From Longman Dictionary of Contemporary EnglishRelated topics: Shapes, patternsV-formationV-for‧ma‧tion /ˈviː fɔːˌmeɪʃən $ -fɔːr-/ noun [countable] CFif birds or planes fly in a V-formation, they form the shape of the letter V as they flyExamples from the CorpusV-formation• Highly gregarious, and collectively noisy, they fly fast and direct, but often with rather laboured wing-beats and in V-formation.