Long time since I've done any domestic flying, but an example of the way they work.
The 767s were used to be scheduled with about an hour on the ground at each port. We could turn them around in less than that, but that gave plenty of time for cleaners, cabin crew, and engineering. It also meant that we had enough time to be able to correct any delays that might have happened previously.
And then someone arrived in the ivory tower, and worked out that you get get much more utilization of the aircraft if you scheduled them for 40 minute turnarounds. So, now they scheduled everything for 40 minutes. We could do than until something went wrong. As soon as there was any sort of delay, it would ripple forward, with no buffer to accommodate it. By the time of the last flights of the day, they were often swapping aircraft around as the scheduled one would be elsewhere, and the crew could well be in yet another location. But, on paper at least, the utilization improved so "Fred" got his huge bonus. In practice of course, delays had increased across the entire fleet. Much the same thing happened with crew, where they had people moving from aircraft to aircraft, never allowing for the time that took, or the effect of prior delays.
Oh, and the marketing induced delays. They used to publish a schedule using flight times that were simply unachievable. The advertised gate to gate time was shorter than the actual flight time. I followed this up, and was told that they were using the same timing as Ansett, and if they published something slower, then people wouldn't book with QF. Ansett's times were equally b/s. The 767 was the fastest aircraft on domestic ops, and both airlines were publishing 737 flight times that were faster than it could possibly do. So, even if you left on time, you were always going to be late, even if all of the dice fell your way. But, now, in an example of extreme stupidity, they then planned the next departure based on this mythical, and unachievable flight time. Even on good days, the delay would increase throughout the day, generally reaching about an hour by the end of a four sector day.
You don't need consultants to sort this out.
Oh, and bonuses. People are employed to do a job, and paid a salary. Why should they be paid any form of bonus for simply doing the job they were employed for. And very badly at that.