Aircraft Economics

Hi all
Don’t know if anyone can help/advise. Writing a paper on economics of aircraft of sub 500 mile sectors, taking into account quick change arounds, passenger comfort, maintenance cost, seat per mile cost
The aircraft I’m looking at in the 19 seat area are

Let 410, Do 228, Twin Otter, Beech 1900,jetstrean 31/41

The 30 seat sector jetstream 41, saab 340, embraer 120, Do 328

The 40 seat sector atr 42, dash 8-200

Any advice or know of any websites which may help
Rob