This multi-line chart displays the yearly number of delayed flights for four airports—IAD, DCA, SFO, and LAX—from 2003 to 2016. It uses `d3.csv` to load the data, `d3.scaleLinear` for the x and y axes, and a `d3.line` generator to draw each line. The code groups data by `Airport.Code` with `d3.group`, colors lines via a `d3.scaleOrdinal`, and renders an SVG with an axis, title, and a `d3.legendColor` legend. Y-axis values reach up to roughly 52,000 delayed flights per year.