I started a new game in the realistic world 1950-2020.
Of course I started at my home airport with 5 gates. I shut the game down en when I logged in again I saw I had only 2 gates left.
To prevent this I leased 3 extra gates again and I created a hub, which is extremely expensive and highly inefficient at the beginning of the game, would never do that if it isn't necessary.
This morning I logged in again and I see that I still have a hub, but only 3 gates left.
More people who have these kind of problems?