Betty, if you had messaged me and asked, I would explain how it works.
Allow me to explain some of what goes on for revenue-maximization airlines ( not really a spamliner, but okay, if you insist on labeling me a spamliner, then I will ignore that from this point forward) and how it works.
first, there are two types of passengers, full-fare passegers (denoted by the green bar) and then there are half-fare passengers (blue passengers(.
For green passengers, there is - for each airport - a daily maximum that that airport can accomodate. For blue passengers, there is NO PUBLISHED daily maximum whatsoever. Rather, the amount of blue passengers you can pick up is a function of several factors:
a) the total number of daily passengers your airline currently services,
whether or not you fly into or out of hubs other alliance members have,
c) the current number of days, weeks, or years you have been in the game.
d) there is a tradeoff between the number of passengers you can pick up and the fare price you can charge,
e) while blue passengers bring only half the revenue that green passengers bring in, there exists no competition for those passengers. Once a revenue-maximizer airline has sufficient daily passenger buildup, the amount of flights that you can place on a route increases as time goes by. Since such airlines are actively expanding routes, hubs, and terminals, the result is a large and expanding increase in the number of blue passengers that an airline can pick should it choose to do so. In order to position yourself to capture those passengers, you must create a hub, after which blue passengers start becoming available to you, slowly at first, but rapidly increasing as time goes by.
f) bulk purchase of terminals in at least 33 gate blocks or greater reduces costs going forward dramatically. The reason I purchase 200 gate blocks is not to gain some advantage that others can't enjoy, but merely because I often run out of slots or end up using all the slots, especially once I have reached the late middle to early middle game years. So yes, at first it appears that I have zero percent gate utilization, but as time goes by and I receive a sufficient quantity of planes to place on those routes, those gates will become mostly filled.