A client can perfectly hire/lease/buy a plane and SEPARATELY hire a pilot to fly him wherever he wants, as long as it's for his PRIVATE USE. What would make the client (and the pilot) conduct illegal OPS, would be to use the aircraft to generate income (that would become COMMERCIAL OPS).
The words "private use" above are superfluous and incorrect.
In my business, I can get hold of a plane, and get hold of a pilot to fly it. The pilot needs a CPL. This is legal, even though this is
business flying.
The important thing is that the flying has to be
incidental to my business (which as it happens is nothing to do with aviation).
The funny thing is that the pilot doesn't even need a CPL (he can be a PPL) if he is my
employee, and always has the option to take the train etc. It is only a pilot who is employment-contractually required to fly that needs a CPL. This is how many business owners (with a PPL) fly on their own business, perfectly legally.
The only other caveat he mentioned is that the requirement for the flight should be initiated by the client and not by the pilot - thus, for example, it would be illegal for a pilot to promote or advertise such an opportunity, and it would be illegal for the pilot to hire the aircraft as part of the service to the client.
Yes, this is what under FAA rules is known as "holding out" and one gets closely quizzed on it in the FAA CPL oral. Holding out is out of the question; you need not just a CPL but an AOC and the whole damned lot. This is why, probably in the whole world, a CPL alone is worthless unless one gets a job in a company with an AOC. Except that you can be a paid pilot with it, retained by a company or by a private individual, to fly
his plane.
The situation w.r.t. legality varies around the world but is not that complicated. If it was, business flying (especially jets) would be finished, because one is carrying one's own employees, sometimes customers or suppliers, or subcontractors, etc. And the whole business is international anyway. And MONEY is always changing hands.
One can have grey areas caused by
who the flight is billed to afterwards. But establishing who a specific flight is billed to could be quite difficult, and obviously if there was an incident then the invoice will not be raised!
An example of a grey area is a G-reg plane, on a Private CofA, owned by a company, and the company owner rents the plane from the company. The act of rental means the plane needs to be maintained to the Transport CofA standard, which multiplies the operating cost through 150hr checks and some component certification issues. But the "rental" is rental only because some adjustment is done in the company accounts (in the Director's loan account) for the private use. The adjustment is done at year-end and if there was an incident then you would obviously not make that adjustment!