We did have a Delta flight (JFK > STT) booked on Jan-5 that was cancelled without notice. I only found out because it was missing when I checked my account. They were able to get us on a connecting flight instead through ATL.

Also, I saw on another post that this is not just on the airlines, but that STT only has two working gates and they are limiting airlines to one flight per day. American is flying just to their MIA hub and Delta to their ATL hub.