American wants you to list on the ID90 website, or call the 1-888 number.
Jumpseat Information > Jumpseat Resources > Airline Jumpseat Policies
It is mandatory to pre-list when planning to ride as a jump seat passenger and you can do this up to several days in advance by using the new online listing system. Within 24 hours of travel call 888-933-5922(888-WE-FLY-AA), option 3