Many have been mentioned before, this is just meant as a guide of sorts to changes in the schedules. This does not include any of the exhaustive list of St. Louis changes. This list is not guaranteed 100% accurate and may be missing some new services. The additional frequencies list is far from complete. I'll keep adding to the lists as I find stuff, so don't forget to check for updates.

New American Airlines Routes
Caracas-Ft. Lauderdale, 15 December, daily
Caracas-San Juan, 1 November, daily
Dallas/Ft. Worth-Buenos Aires, 2 November, 3 weekly
Dallas/Ft. Worth-Cozumel, 31 January, daily
Dallas/Ft. Worth-Providence, 1 November, daily
Ft. Lauderdale-Port-Au-Prince, Haiti, 1 November, daily
Ft. Lauderdale-Santo Domingo, 1 November, daily
Indianapolis-Miami, 1 November, daily
Los Angeles-San Juan, 19 December, 2x weekly
Los Angeles-Tokyo Narita, 4 April, daily
Miami-Minneapolis, 1 November, daily

New American Eagle Routes
Bloomington, Ill.-Chicago O'Hare, 1 November, 4x daily
Chicago O'Hare-Lincoln, Neb., 1 November, 3x daily
Chicago O'Hare-Little Rock, Ark., 1 November, 4x daily
Chicago O'Hare-Moline, Ill., 1 November, 4x daily
Chicago O'Hare-Sioux Falls, S.D., 1 November, 4x daily
Chicago O'Hare-Springfield, MO, 1 November, 4x daily
Chicago O'Hare-Wichita, Kan., 1 November, 3x daily

New Seasonal Routes
Boston-New Orleans, 1 November through 4 April, daily

Resumed Seasonal Mainline Service
Boston-Cancun, 1 November through 3 April, Wednesday/Friday/Saturday
Boston-Port-Au-Prince, 1 November through 1 May, Monday/Saturday
Boston-Providenciales, 1 November through TBD, Satuday
Boston-St. Thomas, 1 November through 30 April, Friday/Saturday/Sunday (Tuesday/Thursday added 16 December)
Boston-West Palm Beach, 1 November through 30 April, 2x daily
Chicago O'Hare-Acapulco, 15 December 1 May, Wedneday/Saturday/Sunday
Chicago O'Hare-Fort Myers, 1 November through TBD, daily (2nd daily ops 31 January through 30 April)
Chicago O'Hare-Hayden/Steamboat Springs, 15 December through 3 April, daily
Chicago O'Hare-Jackson Hole, 15 December through 3 April, daily
Chicago O'Hare-Montrose, Colorado, 20 December through 3 April, Saturdays
Chicago O'Hare-Palm Springs, 1 November through TBD, 2x daily (3rd flight 31 January through 4 April)
Chicago O'Hare-Puerto Vallarta, 15 November through 1 May, Saturday/Sunday (MoTuThFr added 15 December)
Chicago O'Hare-San Jose del Cabo, 1 November through 1 May, MoThFrSaSu (TuWe added 15 December; 2nd SaSu added 31 January through 3 April)
Chicago O'Hare-Vail/Eagle, 15 December through 3 April, daily (2nd flight ops on Saturdays)
Chicago O'Hare-West Palm Beach, 1 November through 1 May, daily (2nd daily ops 15 December through 29 April)
Dallas/Ft. Worth-Acapulco, 1 November through 1 May, daily
Dallas/Ft. Worth-Hayden/Steamboat Springs, 15 December through 3 April, daily (2nd Saturday flight ops 31 January through 3 April)
Dallas/Ft. Worth-Jackson Hole, 7 February through 27 March, Saturdays
Dallas/Ft. Worth-Montrose, 20 December through 3 April, Saturday and Sunday
Miami-Vail/Eagle, 20 December through 3 April, Saturday
New York City/JFK-Grand Cayman, 20 December through 24 April, Saturday
New York City/JFK-Kingston, 15 December through 5 January, daily
New York City/JFK-La Romana/Casa de Campo, 20 December through TBD, Saturday
New York City/San Jose, 15 December through TBD, Monday/Thursday/Saturday/Sunday
New York City/LaGuardia-Vail/Eagle, 20 December through 3 April, Saturday
New York City/LaGuardia-West Palm Beach, 1 November through TBD, daily (2nd/3rd daily 15 December through 30 April)
Newark-Vail/Eagle, 15 December through 3 April, daily

Resumed Seasonal American Eagle Service
Dallas/Ft. Worth-Montrose, 15 December through 2 April, Monday through Friday

*M=mainline, E=Eagle, X=Connection
New mainline service on Eagle/Connection route
Chicago O'Hare-Cleveland, 1 November, from 8E to 3M/5E

New Eagle/Connection service on mainline routes
Dallas/Ft. Worth-Leon, Mexico, 1 October, from 2M to 1M/1E

Additional frequencies
Baltimore-San Juan, 2nd flight Tu/Th/Sa/Su 16 December through 4 April, 2nd flight Mo/Fr 31 January through 3 April
Dallas-Albuquerque, 7th daily, 1 November
Dallas-Baton Rouge, 5th daily, 27 October
Ft. Lauderdale-Los Angeles, 4th daily, 1 November through 4 April
Ft. Lauderdale-San Juan, 4th daily, 1 November
Hartford-San Juan, 2nd flight Sa/Su, 1 November/2nd daily 15 December
Miami-Boston, 6th daily, 1 November
Miami-Bridgetown, 2nd flight Mo/Th/Fr/Sa/Su, 1 November
Miami-Hartford, 2nd daily, 1 November
Miami-London/Heathrow, 2nd flight Sa/Su, 1 November through 21 March
Miami-Montreal, 2nd daily, 1 November
Miami-Las Vegas, 2nd daily, 1 November
Miami-Rio de Janeiro, 2nd flight We/Th/Fr/Sa, 17 December
Miami-St. Maarten, 2nd flight Mo/Fr/Sa/Su, 1 November
Miami-San Pedro Sula, 2nd flight Tu/We/Th/Sa, 16 December
Miami-San Salvador, from 10w to 12w 27 October-14 December and 6 January on; double daily between 15 December and 5 January
Miami-Sao Paulo, 3rd flight Mo/Sa/Su, 15 December
Miami-Tampa, 4th daily, 1 November
Miami-Washington/Dulles, 2nd daily, 1 November
Tampa-San Juan, 2nd daily, 15 December

Reduced frequencies
Dallas/Ft. Worth-Atlanta, from 12 to 10 daily, 1 November

Discontinued/suspended service
Boston-Hamilton, Bermuda, 31 October (although a seasonal route, currently no plans to resume)
Boston-Las Vegas, 1 November through 4 April
Boston-San Diego, 6 January