I would like for some people to have the ability to create a private server, and have a few options in where airlines can fly and the type of world (e.g. You can make it Open World but all airlines can only fly inside Africa etc.). This would also control the people who join, reducing spamlines and more actual airlines. The world creator may be able to see if someone is spamlining, and be able to do a vote with the other players in the world to kick the airline.
I think this privilege to create worlds should be reserved for high ranking AE players, who have been on AE for a while, and are known to play the game properly.
I don't mean to sound demanding, but I would really like this feature (if it is possible).
Also, if this could not happen, I think a 'vote kick' system could be implemented (though it may be tricky, as people may use it just to get rid of competition)