I see we cannot place a msg at your link Tha_APE,so i just do it here.
We have an max 600 plane limit outside HQ.
So is the Too small warning still relevant?
Let say there are only a few routes of 300 +demand and rest is under,makes it already needed for 2 fleets on LH flights.
So means a carrier can only fly LH to prefent a 4th fleet need alot of cash to save up planes and then replace.
So yeah either way you move you gett a penalty for a 4th fleet or a too small warning

The example of what happen in gw3 that an LHR based carrier just closed a base same real day after the local crrier with a hub in LHR went bankrupt,so to gett another player out of business shows we need bounderies as this is not a 1st time either.
It make it really hard for getting a right setting,i understand this part.
Think that we have just 2 levels is the problem.
There is a large group who is too big for the beginners world,but not ready to be based together with the big shots in the game.
So maybe it should be time to devide the settings in the big worlds like in all other games and split so that the players who can check the game 6 times a day and have all the skills to give others a hard time and also something in the middle for the players who just like the idea of beeing a real ceo and have ave settings.