I have noticed an additional earlier flight to LAS in November and December (not every day but just occasionally). Also an earlier return flight. Do you think this is an additional flight or are they changing the time and will move existing passengers when they have it all loaded. A call to CSA was NO help . I have a January trip booked and would like to change to both these earlier flights hopefully at no charge.
Any ideas??

I imagine it might be extra capacity on peak days with one of the new e90s they'll be getting this fall.

They have a second MKE-LAS trip loaded starting 11/17 and running through 12/21. This flight leaves MKE at 1:05pm Monday through Saturday, except some Thursdays it operates at 8:45am and other Thurdsdays it does not operate.

What is odd is that at this point, there is not a return flight nor does there appear to be any other schedule addition or adjustment in MKE to make that work out. The added flight is an Airbus, and for it to leave Milwaukee at 1:05pm (most days) means the aircraft has to arrive MKE by no later than about 12:25pm. That's too early for this to be the afternoon leg of something like MKE-CUN-MKE, MKE-Florida-MKE, MKE-LAS/PHX-MKE, etc.

Clearly some other changes will need to happen to the schedule. Obviously I'm curious to see what other changes are being made to make this work.

As for your specific travel, sit tight and see if the upcoming schedule changes affect your days. If your existing flight operates but there is another one, you would likely be required to pay a $50 change fee plus or minus the fare difference, if any.

I have now noticed that there are no direct LAS - MKE flights loaded for Tuesdays and Wednesdays in December. However, there are now two flights on Thursdays. Do you think this schedule will change again??

The December schedule is showing some flights pulled from off-peak days during the predictably slow perdiod between Thanksgiving and Christmas. Most these are late-PM flights on Tuesday/Wendnesdays. In the case of MKE-LAS they are running an additional Thursday flight to add capacity to peak days.

January doesn't show any such adjustments yet, although I wouldn't be surprised. If there are to be long-anticipated cutbacks in the FL/WN Milwaukee east-west operation, they seem unlikely to come until March or later. As such, this winter will have as much overcapacity as last winter, when both FL and F9 averaged half-empty planes. And so it would not surprise me to see these sorts of off-peak flight reductions pushed into January. But we shall see.