We have family in SAT, so we fly frequently between our home in ATL and there.
F9 stopped flying nonstop between ATL and SAT last year, so we have used SW or DL which still have nonstops.
In early April, we were planning another trip to SAT in June, and miraculously nonstop flights on F9 showed up! And we got free checked bags!
Then today, not even two weeks later, we got an email saying our flights were cancelled and offering to be rescheduled on an overnight flight through LAS, totaling almost 20 hours. We, of course, elected to cancel and get a refund.
These schedule changes have no rhyme or reason. It's almost like these nonstops were a bait out there for a couple of weeks, only to be switched to connecting abominations later.
Do not count on F9 if you need to be somewhere.