Extended family flew TPE-HKG on Dec. 15th on CX, boarded CX 830 (HKG-JFK) & departed on time, checked it overnight & showed 2 hour delays (it was off the coast of Japan) - landing 2 PM instead of typical noon arrival @ JFK.

For whatever reasons, Flightstats timeline showed arrival time changed again - now showing back to on-time arrival around 30 minutes from now, noon time locally here. Must be very strong tailwind on the crossing & overcoming air traffic control ??

Looked at CX 840 and CX 846, both inbound toward JFK and (was) showing delay.