I am not in the game world so I can't view your airline but you may want to let the Q400 go when its lease renewal comes if you are really stuck and use the money you save from leases to get another ATR (go for the larger model if possible). The decreased maintenance cost for having only a single model type in your fleet should help you start gaining.
Another thing to check is ticket pricing. If you haven't done it in the past month or two of game time, go Routes -> Price Management -> check and confirm to reset prices of all routes at the bottom of the page. Inflation happens, fuel prices go up, and ticket prices won't go up to match those unless you reset them to default every once in a while. You might be missing out on a few dollars per ticket, which if you look at your pax load in the past month, should give you an idea of how much money you could be missing out on. $2-3 extra per ticket, while small by itself, ads up fast when you are transporting 1000's. Not keeping ticket prices up-to-date can crush a larger airline that is transporting tens of thousands or even millions of pax in a month.
Since you are using small planes, I assume your routes are short. If they aren't already, consider configuring them to be compact seating instead of standard to fit more pax on short flights where they don't mind it over the short flight time. Getting an extra 10 pax on a flight can matter a lot in the long run for a small airline.
Drop your CEO salary. The CEO is you so you can drop it down without crippling operations. It just affects your personal wealth in the sim, unless you are shooting to be loaded at the end of game world, so you should be able to safely lower it and save a decent amount come Tuesdays.