Https://pressbooks.pub/allairlinestravelexpertise/chapter/%e3%80%90faqs%e3%80%91what-day-of-the-week-are-american-flights-cheapest/ https://pressbooks.pub/allairlinestravelexpertise/chapter/%e3%80%90faqs%e3%80%91what-day-of-the-week-are-american-flights-cheapest/