What is Part 135 and how does it differ from Part 91?

• A. Part 135 governs on-demand air taxi and commuter operations; Part 91 governs general aviation under civil rules.
• B. Part 135 governs general aviation under civil rules; Part 91 governs on-demand air taxi.
• C. Part 135 is unrelated to on-demand services; Part 91 covers all aviation.
• D. Part 135 requires instrument ratings for all flights.

Answer: (A)

The key idea here is that aviation regulation splits commercial, for-hire operations from general, non-commercial flying. Part 135 covers commercial operations that transport passengers or cargo on an on-demand basis (air taxi) or as commuter services. These flights are conducted under a certificated operator with specific operating rules, maintenance programs, crew qualifications, flight planning, recordkeeping, and other safety requirements designed for for-hire transportation. In contrast, Part 91 governs general aviation—private or non-commercial flights under civil rules with more flexibility and fewer prescriptive requirements for operations, maintenance, and staffing.

So, the statement that Part 135 governs on-demand air taxi and commuter operations while Part 91 governs general aviation under civil rules matches how the FAA separates commercial, customer-arranged transportation from private flying. It’s not true that Part 135 is unrelated to on-demand services, nor that Part 91 covers all aviation, nor that Part 135 universally requires instrument ratings for every flight—the latter depends on the operation and weather/IFR requirements and isn’t a blanket rule.