One data point for the future.

DL 782 JFK Departed 7:40AM(scheduled 7:05AM)
DL 118 JFK Departed 12:25PM(scheduled 11:50AM)
DL 086 JFK Departed 5:09PM(scheduled 3:25PM)

AA 490 JFK Departed 8:14AM(Scheduled 7:00AM)
AA 1510 JFK Cancelled 11:40AM
AA 1048 JFK Cancelled 1:30PM
AA 530 JFK Cancelled 4:00PM
AA 2086 JFK Cancelled 7:20PM
AA 882 JFK Cancelled 9:30PM

DL 2151 LGA Departed 7:21AM(shceduled 7:00AM)
DL 670 LGA Departed 10:54AM(shceduled 10:30AM)
DL 870 LGA Departed 3:37PM(scheduled 3:00PM)
DL 2098 LGA Departed 7:19PM(scheduled 6:20PM)

AA 1114 LGA Departed 6:21AM(Scheduled 6:00AM)
AA 1256 LGA Departed 9:11AM(Scheduled 7:25AM)
AA 2008 LGA Departed 11:16AM(Scheduled 10:55AM)
AA 1132 LGA Departed 12:18PM (sceduled 10:00AM)
AA 508 LGA Cancelled 12:50PM
AA 1402 LGA Cancelled 2:20PM
AA 564 LGA Cancelled 4:00PM
AA 1908 LGA Cancelled 6:10PM
AA 2010 LGA Cancelled 7:10PM
AA 1226 LGA Cancelled 8:30PM

UA 1133 EWR Departed 7:17AM(scheduled 7:00AM)
UA 1224 EWR Departed 10:21AM(scheduled 9:50AM)
UA 1290 EWR Departed 2:25PM(scheduled 1:43PM)
UA 1186 EWR Departed 5:06PM(scheduled 4:38PM)
UA 1226 EWR Departed 8:35PM(scheduled 7:59PM)

AA 1212 EWR Departed 8:20AM(Scheduled 8:05AM)
AA 932 EWR Cancelled 1:25PM
AA 1382 EWR Cancelled 9:00PM

Confirmed there was no cancellation for DL/UA out of MIA today.
Even if we consider MIA is a hub for AA, AA can do better than that.