So... changing the model to out and back flying with all aircraft back in home base at night for maintenance? Sounds good in theory, but one problem is (especially for a large, or "growth", airline) there simply isn't enough parking space at night for all of those aircraft. Not nearly enough. For example, Delta parks aircraft overnight all over the southeast because there simply isn't room in Atlanta. Now you gotta pay to overnight the crews and have maintenance at many of those outstations.