i have a reccomendation. so my idea was if you create another GAME yes Game but instead or airport realated it is airline so you create your own airline as such. and maybe if its possible the airline you created in (example name for the new game) Airline CEO you could use in Airport ceo
If you want create airlines for ACEO, check the modding functions.
Yes but the devs would have to spend time into making a completely new game compared to just improving Airport CEO.