Originally Posted by xliioper

As I just noted above, the JFK-LAS route has now been pulled from D1 revenue fare rules as of 8/19. The same date that JFK-SAN was pulled. When it was in the fare rules, 763/764 equipment would be marketed as D1. Now that the route is no longer in the fare rules, all flights will be marketed as FC regardless of equipment type. This is not something they just make up on the fly, it's governed by the fare rules. There was a issue with JFK-SEA flights on A330-900neo equipment being sold as FC earlier in the year as they had not updated the fare rules to include this equipment type on this route as a D1 flight. Once the fare rules were updated, the equipment was marketed as D1. The current list of D1 routes/equipment combinations from the fare rules can be found in this post --

As with JFK-SAN, the award fare rules still include JFK-LAS as a D1 route which results in strange flight search displays like this --