An air distribution assembly for vehicles, comprising a first flap, able to rotate around a first axis, a second distribution flap, able to rotate around a second axis, and a geared transmission device that connects the first and the second flap to each other. The transmission device comprises at least one gear wheel including a first and a second element able to rotate relative to each other and an elastic element positioned between the first and the second element to allow a relative rotation motion between the first and the second element.