Perhaps time to introduce different server times as follow:
Speed game: Day changes every 20/25/30 minutes
Normal game: Day changes every 35/45 minutes (perhaps even every 60 minutes)
The survey indeed concluded 30 was the most popular and I think those people votes should be respected in the form of "30 minute" servers
Strongly agree, I used to manage over 500 planes in one game and that was painful... especially one night I was receiving over 100 planes at the same day.....
Thats your problem as 500 is exceptionally high. Most players in the game stay between 60 and 200 which can be done quite well in 25/30 minutes. Also people often play in multiple scenario's which adds up to that. Its space time continuem actually.... If you have two airlines you can only spend half your time on each of them. So I think it's up to players own descretion to start up a second, third, fourth or even a fith airline... but don't come here and cry for another additional few minutes couse you can't cope with the time your airlines ask from you.
Nothing personal ofcourse... but just what I experienced myself when having four airlines. (for me that was too much)