...very, very quickly.
The costs are large. If you find this mythical place what's the chance that someone else is already there. Alternatively where do you get your maintenance done?
Depending on which bit of the world you're in you'll be up for:
1. An AOC. Expect a fair bit of investment in this. Can include Authority vetting of of financial resources
2. Appropriate organisation structure: Chief Pilot approved & appointed (minimum experience requirements must be met), maintenance controller, many & varied paperwork trails to be used & kept eg ops manual, fuel monitoring, pax manifests, annual a/c usage surveys from the authority etc etc
3. An aircraft. Buy? Lease? What sort? Don't forget the more onerous maintenance requirements for public transport. Insurance. Fuel supply availability AND cost.
4. Staff. Might just be you but who answers the phone/organises the next group while you're doing a flight?
5. Marketing, including alliances/special deals with the local tour operators to feed in the pax.
6. Depreciation AND what return could your funds have in different investment?
7. Premises. All the usual premises costs.
8. Replacement pilot(s) while someone's away on holidays. Induction costs to ensure they operate IAW your operations manual. Reduced staffing levels during the period instead? What about the 'other' a/c if this means pilot numbers=aircraft numbers - 1?
These just off the top of my head. It goes on and on and on and....