This suggestion is primarily aimed at increasing the functionality of the auto-scheduler, by adding new controls for the user.
The first control I would like to suggest is the ability to manually control what times the auto-scheduler will schedule flights for. As it currently stands once night flights are unlocked, flights will be scheduled 24/7 and there isn’t really anything you can do about it. There are many situations where it would be advantageous to have daily downtime at your airport, to allow the adjusting of baggage handling and taxiways, or to simply serve as a defense against runaway flight delays (small reoccurring delay that propagates through multiple flights causing major issues).
The second control I would like to suggest is the ability to disable the auto-scheduler for a specific gate. This would be incredibly helpful when you need to close a gate for construction, without cancelling any flights. Currently you either have to schedule all your flights manually, which can be hectic at a large airport, or cancel a bunch of lights that are assigned to the gate, which can be costly when it comes to airline reputation.
My final suggestion is a allowing each gate to be assigned to a specific airline, this could be done either through the scheduling window or the stand window. This will add realism, as most major carriers operate out of specific gates at the airports they service, as well as improve game play by preventing issues relating to a single gate from hurting your reputation with all airlines.
The way this could work, is by default, all gates will act the way they currently do, however the player can select a specific airline (out of airlines that currently have contracts with you) and assign that gate to that airline. From that point on, only that airlines flights will be scheduled for that gate, and the auto-scheduler will favor scheduling flights from that airline to gates that are assigned to it.
For example: I have an airport with four gates(A1-4), and contracts with Maple, Forrest, and Sky Link. I assign gates A-1&2 to Maple, A3 to Forrest, and leave A4 unassigned. The auto-scheduler will only assign Sky Link flights to A-4, and will attempt to assign all Maple and Forrest flights to there respective gates. However, with only one gate assigned to Forrest, the auto scheduler runs out of room at A3, however Sky Link is at a lower rep, and only offered 3 flights, so there is plenty of room in the schedule at A4. The auto-scheduler will then schedule Forrest flights at A4 until A4 is full, or more room opens up at A3.
Maple on the other hand has two gates and the scheduler will schedule flights at the earliest opening at either of those gates, only using A4 if both A1&2 are full.