Before the summer, they did. Just looked at AA is 33.8% D0 for the month in DFW. Yesterday and today are around 33%. Clear, summer days with no weather.
My last trip:
Day 1: First leg delayed 3.5 hours, 2nd leg delayed, last leg removed for duty time.
Day 2: First leg removed due to Day 1. Leg 1 departed 30m late, leg 2 15 minutes late, leg 3 was only 5 minutes late.
Day 3: First leg delayed 2 hours, 2nd leg 2 hours
Day 4: 5 minutes late on one and done leg
Some of the stuff is comical. They schedule us for an airplane that is AOG and then it gets pushed back. Wait for a new inbound, but it is over fueled. Dispatch/Ops/Fuel can't coordinate the defuel. We go back and forth with all 3 multiple times and finally get defueled, but they botch it and we decide to just burn the rest in the air and run the APU the whole time and pull the boards at cruise.