I was wondering how much profit should i be making per flight and what is depreciation of flight equipment and how do i fix this

Profit: Depends. "Healthy" margins on flights not solely intended to feed others usually range from 20% to around 50%, maintaining the possibility to transfer to other flights.

Depreciation: No way to fix it. It ages and depreciates. It’s not a disbursement, though, but just an expense.