EWR is only mainline hub flying and LGA only has STL as non hub mainline flying. A number of domestic routes that were served out of LGA (TPA, MCO, FLL) have been moved to JFK. Eventually AA will build up both JFK and LAX even more. LGA used to have mainline flying to MCI, ATL, MSP, AUS/HOU (and maybe others); all gone or now AE.