https://intercom.help/cox-media-dba923b7029e/en/articles/10781968-what-is-the-cheapest-day-to-buy-flights-on-united-airlines
https://intercom.help/cox-media-dba923b7029e/en/articles/10781968-what-is-the-cheapest-day-to-buy-flights-on-united-airlines