Cyrano has added some excellent advice, that is a great post!
I have started a UK scheduled airline so I would approach things as Cyrano says a little more simply.
Restrict your search to one or two aircraft types and then get dry lease rates from lessors ( most will help if you ask nicely) and find the approximate maintenance costs per hour, You will not get exact costs unless you know the hours to cycles ratio but as this is a study and not the real World it will not matter. Get the airport costs, usually published, crew costs, fuel burns and cost for the aircraft you choose. The fares, use the first class train fare as a guide if in doubt. Cyrano has covered most of it.
Learn the difference between wet, dry and damp lease and all about maintenance programmes,reserves and costs.
I can only say again concentrate on the boring bits, as Cyrano has said I hate to think how many start ups I have seen that never happened where people arrive with glossy photos, great plans for uniforms, paint schemes etc and totally forget the economics!
My own experience is somewhat out of date now but willing to help where possible.