I belive that this game should introduce progressive admin cost for airlines.
Currently small airlines do not have any advantage over mega airlines. Unlike in reality, small airlines have advantage in lower admin cost due to smaller scale.
With progressive admin and route planning cost involved, larger airlines would be focus on getting bigger planes and concentrate on profitable routes instead of 1000+ dashes. This also give small airlines some advantage over larger one (and also filling up those empty space in old server)