According to airlineroute.net, DL will be reducing its JFK-NRT flight to six times weekly this winter, from October 3 thru March 26, not flying on Wednesdays:
http://airlineroute.net/2015/09/11/dl-jfknrt-w15/
The same source earlier revealed that DL would reduce SEA-HKG to just two weekly nonstops while resuming NRT-HKG five times weekly:
http://airlineroute.net/2015/09/07/dl-hkg-w15/
When AA reduced its ORD-NRT flight to five times weekly, its joint venture partner JAL continued to fly daily, meaning that AA and JAL combined offered 12 weekly flights on that route. DL has no joint venture partner to pick up the slack on Wednesdays from JFK.
http://airlineroute.net/2015/09/11/dl-jfknrt-w15/
The same source earlier revealed that DL would reduce SEA-HKG to just two weekly nonstops while resuming NRT-HKG five times weekly:
http://airlineroute.net/2015/09/07/dl-hkg-w15/
When AA reduced its ORD-NRT flight to five times weekly, its joint venture partner JAL continued to fly daily, meaning that AA and JAL combined offered 12 weekly flights on that route. DL has no joint venture partner to pick up the slack on Wednesdays from JFK.