I think I've had delays on a handful of flights over the past couple of months (I do typically fly in evenings). But if there's an issue in the morning and the plane is coming from the west coast, it's going to slow down the rest of the scheduled route.

Last week I had a flight from MSP to STL. There was a plane swap at LAX that delayed getting into DIA....and then into MSP...and then into STL...and they flat out cancelled the continuation to Dayton after that.