Both Citation Part 91 pilots and Flight Instructors require commercial pilot certificates, with additional ratings for specific aircraft. Citation Part 91 pilots operate under FAR Part 91 regulations, primarily for private or corporate flights, often in a corporate or charter environment. Flight Instructors, on the other hand, are certified to teach student pilots and operate under FAR Part 61 or 141, focusing on training in flight schools. While both roles involve flying, Citation Part 91 pilots focus on operational flying, whereas Flight Instructors focus on training and education.