I thought I started to notice a trend with Delta's domestic availability from the NY area, so I checked a bunch of cities and I came up with the following (all nonstops):
JFK-CVGJFK-CLEJFK-DTWJFK-ORDJFK-PITNYC-MKEWant to only spend 12.5K for that domestic one way?
Wait until Feb 24.
Willing to spend 5K more?
You can go Feb 17.
I can't imagine this is a coincidence.
2 weeks and 3 weeks out are big dates when fares go up for the LCCs, and I would assume someone at Delta decided to follow suit with the miles availability.