Join Date: Jan 2011
Location: Philadelphia, PA
Programs: AAdvantage Exec Platinum, Hertz #1 Club Gold Five Star, IHG Platinum, Marriott Gold, HHonors Silver
Posts: 2,457
Well, you'd then fly AA to a United hub that flies to RDD and have two separate tickets. If you do this, be sure to have a long layover and backup plans if you miss your connection.
Alternatively, you can also see if you can get a site like Expedia or Orbitz to generate a single ticket with AA and UA legs.