Story
It's the dawn of the Golden Age of Aviation on planet Prester, and retro-futuristic sky vehicles known as vanships dominate the horizon. Claus Valca – a flyboy born with the right stuff – and his fiery navigator Lavie are fearless racers obsessed with becoming the first sky couriers to cross the Grand Stream in a vanship. But when the high-flying duo encounters a mysterious girl named Alvis, they are thrust into the middle of an endless battle between Anatoray and Disith – two countries systematically destroying each other according to the code of chivalric warfare.
Synopsis via AniList (English).