ok. thanks for all your answers. I want to specify.
Let's say for example I own one little cessna 172 (or an Airbus A380..) and I fly bos-ewr (and back) at least once a week on a fixed date.
I want to save/make money and offer people to fly with me (transport licence, insurance etc. everything is available/paid for).
There has to be a database I guess? Where do pilots/airlines register for expedia, kayak etc.?
Is there a minimum requirement to be called an airline/route service etc.?