NOTE: Changes have been implemented 01 March 2017, as tweeted by JonNYC. See American Airlines announces new boarding policy effective 1 March 2017

Link to March 1 boarding process on aa.com.

On March 1, 2017, American Airlines will launch a new, simplified boarding process. In the future, all customers will be assigned a group number (1 through 9) based on their ticket type, elite status level and priority. We will call the group number in our announcements rather than all customer types. The boarding order will be the same, with only minor exceptions. The change is in how we refer to each group on boarding passes and announcements. Our ConciergeKey members will be invited to board prior to general boarding.

• Preboard: Pax requiring assistance, ConciergeKey (+ Five Star customers)
• Group 1 - First class or 2 cabin international Business class / Active duty U.S. military with military I.D. link(Business on a 2-class international plane)
• Group 2 - Executive Platinum / oneworld Emerald / 3 Cabin Business class
• Group 3 - Platinum Pro / Platinum / oneworld Sapphire
• Group 4 - Gold, oneworld Ruby, Air Pass, Premium Economy, Executive Citi credit card, purchased Priority Boarding
  Group 5 (preferred boarding) - Main Cabin Extra (excluding Basic Economy), Eligible corporate travelers**, Other AAdvantage eligible credit cards*
• Group 6 - 8 - Coach Groups, Basic Economy on longhaul transoceanic
• Group 9 - Basic Economy within the U.S., Canada, Mexico & Caribbean

*Eligible AAdvantage® credit cardmembers (on American Airlines flights) include:

• Citi® / AAdvantage® Platinum Select World EliteTM Mastercard®
• CitiBusiness® / AAdvantage® Platinum Select World EliteTM Mastercard®
• Citi® / AAdvantage® Platinum Select® American Express® Card
• Citi® / AAdvantage® Platinum Select® Visa Signature
• AAdvantage® AviatorTM Silver Mastercard®
• AAdvantage® AviatorTM Red Mastercard®
• AAdvantage® AviatorTM Business Mastercard®

NOTE: AA recent policy has included "Should you arrive at the gate after Priority customers have been called, you may bypass the General Boarding lines and enjoy the convenience of boarding anytime via your new dedicated boarding lane." (American Airlines policy.)

See Ben Schlappig / Lucky's blog here.

NOTE: AA gate agents seem to often and unpredictably begin boarding earlier than the scheduled times mentioned below.

50 minutes prior to departure From/To the United States and:="4"%Europe
Middle East
Asia
South American destinations: Asuncion, PY; Brasilia, BR; Belo Horizonte, BR; Curitiba, Br; Buenos Aires, AR; Rio de Janeiro, BR; Sao Paulo, BR; Lima, PE; Montevideo, UY; Porto Alegre, BR; Recife, BR; Salvador, BR; Santiago, CL; Sao Paulo Viracop, BR

45 minutes prior to departure - From/To the United States and:="4"%Caribbean
Central America
Hawaii
Mexico
South American destinations: La Paz, BO; Santa Cruz, BO; Maracaibo, VE; Caracas, VE; Bogota, CO; Cali, CO; Medellin, CO; Guayaquil, EC; Quito, EC

35 minutes prior to departure - Domestic on these aircraft types: A321, A321S, A330, B757, B767, B787, B777="4"%Within the 48 contiguous states
Alaska
Canada

30 minutes prior to departure - Domestic on these aircraft types: A319, A320, A321T, E190, S80, B737="4"%Within the 48 contiguous states
Alaska
Canada

Conditions of Carriage (Link

"Arrival at Gate
You must be at the gate and ready to board the aircraft:

15 minutes prior to scheduled departure for flights departing from points -within- the U.S., Puerto Rico, and Virgin Islands

30 minutes prior to scheduled departure for flights departing from points -outside- the U.S., Puerto Rico, and Virgin Islands, i.e., Canada, Mexico, Europe, Asia, Central/South America, Caribbean, Bahamas, Bermuda"

For gate arrival, AA states: "Recommended before your flight: Link

30 minutes

Be at the gate, ready to board. Doors close 10 minutes before departure – once they close you'll be denied boarding."