One more question: Are you flying High Density seating?
In my personal opinion, if you are leasing, 8 aircraft is borderline for profitability, maybe you could balance out if the routes are uncontested.
13-14 aircraft onwards, some cash starts trickling in.
At this point, you have to expand with the rest of your cash and maybe target some smaller airports where slots won't eat up so much of the cash in hand.