The best way to get cheap tickets is to buy tickets on days no one travels. Why are the ‘cheapest days’ cheap? It’s a matter of demand; most people don’t want to fly on a Tuesday, Wednesday or Saturday so airlines have trouble filling their planes. And because empty seats bring in no revenue, airlines fill them by lowering prices. Cheapest days to fly, domestic: Usually Tuesdays, Wednesdays, Saturdays. Also, Fifty-four days before takeoff is, on average, when flights within the continental U.S. are at their absolute lowest price.