About a decade ago, I was part of a startup trying to disrupt crew scheduling. It's a non-trivial operations problem when you aim to honor crew preferences, union-negotiated affordances, FAA legalities, etc. We were only involved in the pre-planned schedules. At that time, the airlines we were courting had entirely different human-hravybsystem to resolve real time issues. There was some level of reserve redundancy baked in so the human planners had some wiggle room to work with... but redundancy is expensive to maintain. As a relatively new engineer at the time it was a pretty neat domain with big $$$ at stake. As it turns out, pretty much nobody wanted to take the risk on a new system even if it had provably better schedules for all parties. All it takes is one snafu for the whole thing to turn into a major regret.