I think Delta has accelerated some of the “taking back” of its brand and its flying.

UA has some interesting corners it has painted itself into in regards to its regionals and will likely follow Delta’s lead in the coming years with a large order of 100 seat aircraft.

AA I think has been watching closely but hasn’t quite seen fit to pull that trigger just yet. First they will start parking 50 seaters (which apparently we are going to start seeing in 2019). Then as it becomes necessary they will reduce their 76 seat flying and that is likely when we would see a Group 1 aircraft order from AA. They have a good thing (read: profitable) going with their regionals right now.