Regardless of your baggage arrangements, you can check in online 24 hours before departure, and as close as 45 minutes before your plane departs.
Passengers can take up to 10 bags with them on most American Airlines flights. For Economy travellers, all bags must be smaller than 158 cm square and weigh less than 23 kg. First Class or Business travellers enjoy a slightly higher weight limit of 32 kg. In almost all cases, the first item is complimentary, and further free bags are available for different tiers of AAdvantage members.