Refers to a person who operates an aircraft. Often used in formal or occupational contexts, such as licenses or job titles.
He is a pilot of a passenger plane.
Getting a pilot's license requires rigorous training.
操縦士 stresses the technical skill of operating the controls of an aircraft, whereas 飛行士 is a broader term for someone who flies as a profession.
copilot
Compound of 操縦 (そうじゅう, 'steering, control') and 士 (し, 'person of a certain profession').