Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.1030 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)
AA does not offer Business Class on the vast majority of its domestic U.S. flights: only First and Coach (Economy). So 30K Avios for DCA-MIA in F is correct -- and probably a very poor use of Avios.