Like with every JetBlue flash sale, this one comes with some fine print you should consider before you start packing all of your flannel shirts. Specifically, you'll have to travel between October 11 and December 20, although there are a bunch of blackout dates in late November. Oh, and the sale only applies to "Blue" fares, so if you want to check a bag it's going to cost an extra $25, and $35 for a second bag.
All said, fall isn't exactly the most ideal time to travel, but between the changing leaves, all the PTO days you haven't used yet, and the looming threat of stressful holiday travel, you have at least three reasons to try. Best of luck.