Airline flight scheduling method differences
There are many academic papers available for general airline scheduling topics. Airline flight schedule planning is a huge topic, existing within the more general field of Operations Research. The models and algorithms used are not simple by any means, and thus there could exist many kinds of differences between the methods used by each of the different airlines.

Considering such models are part of how airlines gain a competitive advantage, specific airline methods, at least for now, are proprietary information.  Perhaps this will not always be the case, but it would take a change in the  way the airline industry operates for this type of information to be publicly available.

That being said, the data about the output of those models are freely available, collected by the U.S. Government (see the Bureau of Transportation Statistics).

Theoretically, one could mine the available data to reverse-engineer some differences, but these will be theories at best.