We used one in January. It looks a bit like a car seat when fitted but a soft seat, not hard plastic. Can't remember exactly, but the straps were quite complicated (needed stewerdess help) and is attached with the plane seatbelt. Roomy enough for a big baby up to 2. Don't be alarmed if its not in the seat when you get on the plane as we had to ask when we boarded, sorry don't have any pics, but DS1 slept comfortably for hours so it was worth every penny to get that seat.
Claire xx