At most AA stations, you can check bags anytime on the calendar day of departure. However, there are some airports with tighter rules:
- only 6 hours before departure time for HNL departures
- only 4 hours before departure time for 18 other AA stations (see list at link below).
Also, there are exceptions for very late redeye flights (i.e. flights that depart 12-1am), where you clearly can check your bags the night before when you get to the airport, even though it is technically the previous calendar day.
Full details here:
https://www.aa.com/i18n/travel-info/...nd-arrival.jsp