https://intercom.help/travelling-6e65e4fbbe18/en/articles/10873726-f-a-q-what-is-the-cheapest-day-to-buy-frontier-tickets
https://intercom.help/travelling-6e65e4fbbe18/en/articles/10873726-f-a-q-what-is-the-cheapest-day-to-buy-frontier-tickets