So the boarding problem is complex optimization problem for the airlines but with various paradoxical qualities. A) Airlines benefit from having tiered costs f

So the boarding problem is complex optimization problem for the airlines but with various paradoxical qualities. A) Airlines benefit from having tiered costs for tickets because their ideal situation is having minimal costs but charging each customer what the customer is willing to pay. B) But of course, reducing total load times reduces the time planes spend on the ground. This isn't just reducing travel time but also reducing the number of planes the airline needs to take N passengers to their destination. Obviously, airlines care about their own time-costs more than the passenger's time costs - why the airline briskly takes their passenger to some out of the way hub and then has the passenger wait five hours of their own time. So between these factors you get a pretty complex problem. That thing is that when you get into such complexity, the best strategy can be nothing more than incremental, greedy optimization. IE, it's surprising complex "best approaches" aren't being tried here.