A surgeon.
A person who operates a machine is called an operator and in some cases a machinist.
projectionist
a captain
Motorist.
doctor
A person who operates a milling machine is called a milling machine operator, milling machinist or a machinist.
a person who farms; person who operates a farm or cultivates land.
A Sodbuster is a person who operates a farm.
creamatorium worker
Barista
The front person(The Pilot) operates all the controls and movements of the jet while the back person(The Missile Targeter) just controls and operates the full gunning and missile launching activities.
A person who is identified as a "restaurant keeper" in the 1900 US Census is a person who owns and operates a restaurant, just as an innkeeper is a person who owns and operates an inn (the forerunner of a hotel).