Also referred to as 'wash line flags'.
Bunting (or bunt) is any festive decorations made of fabric, or of plastic, paper or even cardboard in imitation of fabric. Typical forms of bunting are strings of colourful triangular flags and lengths of fabric in the colours of national flags gathered and draped into swags or pleated into fan shapes. The term bunting is also used to refer to a collection of flags, and particularly those of a ship. The officer responsible for raising signals using flags is known as bunts, a term still used for a ship's communications officer. Wikipedia