As a previous posted stated, its okay to run CRJs if you OWN the aircraft. Bad idea if you lease it.
It may SHOW that your CRJ is making profit. But that only routes leasing fees, route cost, fuel. But I'm assuming your CRJ is making maybe $200,000 per week or less. Reality is its not sustainable if you keep increasing your CRJs. Your profits will still be razor thin.
While this is an EXTREME example...it good to show how your staff cost will exponentially sky rocket
Airline A: 1 Aircraft-A380
# of Pilots: 2
#of Pax: 853(high density)
# of A Checks per week: 1
This airline only has ONE aircraft. Hires 2 pilots
Airline B: 15 Aircraft CRJ-200
# of Pilots: 30
# of Pax: 50(high density)x15planes= 750 pax
# of A Checks per week: 15(aka, maintenance staff goes up)
This airline has 15 AIRCRAFT!! But already has 30 pilots! More maintenance workers.
As you see, the airline with 15 Aircraft is actually worse off and paying A LOT or staff than that airline operating just 1 aircraft.
In terms of your growth, you are based out of CLT. Currently you don't have major competitors there which is good. So as of right now, its hard to get aircraft and most popular models will take FOREVER to get.
I'm sure you don't want to wait 4-5 years to get an A320 or a B737.
My personally suggestion for you at this point is getting the B717. Current wait time is nothing. You can have your first aircraft in 3-5months. Use the B717 to replace your CRJ routes. Launch your B717s on some quick 200-400NM routes 4-5times daily. You'll have a cash cow. Do not send them to max range though, you don't want to go transcon with the B717. But it will give you enough capital to invest in other aircraft.