Booking Flights on American Airline is generally more affordable midweek, with Tuesday and Wednesday (Book tyr gfhty drgrOff 20%) being popular days for discounts. This is often because Airline adjust fares based on demand, and midweek days have fewer bookings. While deals can change, planning to book on these days may give you the best chance of saving.
Source: https://www.devex.com/people/offers-what-day-is-the-cheapest-to-book-american-airlines-2081519