Seems like there’s an NYC delay program affecting only delta. Here are the details from FAA website with regards to JFK:

ATCSCC ADVZY 033 JFK/ZNY 12/27/2025 CDM GROUND DELAY PROGRAMMESSAGE:
CTL ELEMENT: JFK
ELEMENT TYPE: APT
ADL TIME: 1017Z
DELAY ASSIGNMENT MODE: UDP
ARRIVALS ESTIMATED FOR: 27/1020Z - 27/1559Z
CUMULATIVE PROGRAM PERIOD: 27/1020Z - 27/1559Z
PROGRAM RATE: 5
FLT INCL: CONTIGUOUS US DEP CARRIER DAL ONLY
DEP SCOPE: (2NDTIER) ZAU ZTL ZDC ZNY ZJX ZOB ZBW ZID ZMP
CANADIAN DEP ARPTS INCLUDED: NONE
DELAY ASSIGNMENT TABLE APPLIES TO: ZNY
MAXIMUM DELAY: 259
AVERAGE DELAY: 157
IMPACTING CONDITION: OTHER / OTHER
COMMENTS: DAL MAINLINE AND SUBS ONLY, AIRLINE REQUEST. EFFECTIVE TIME:
271019-271659SIGNATURE:
25/12/27 10:21

Anyone knows what’s going on?