Part 91 vs Part 135 Aircraft Management: What’s the Difference?

If you own a business aircraft, you will run into the terms “Part 91” and “Part 135” early and often. They refer to two different sections of the Federal Aviation Regulations, and the difference comes down to one question: is the aircraft being flown privately, or is it being offered for hire?

Part 91: Private Operation

Part 91 covers the general operating rules for private flights. When you fly your own aircraft for your own purposes — business or personal — you are operating under Part 91. You have broad flexibility over scheduling, crew, and how the aircraft is used, and the regulatory burden is lighter than commercial operation.

Part 135: Charter for Hire

Part 135 is the FAA air carrier certificate that allows an aircraft to be chartered — flown for paying passengers. It carries stricter requirements: defined crew duty and rest rules, more rigorous maintenance and inspection programs, drug and alcohol testing programs, and operational control held by the certificate holder.

Why It Matters for Owners

The practical decision most owners face is whether to place their aircraft on a management company’s Part 135 certificate. Doing so allows the aircraft to generate charter revenue when you are not using it — revenue that can offset the fixed costs of ownership like hangar, insurance, and crew. The trade-off is that the aircraft must meet the higher Part 135 standard and is, at times, scheduled for charter trips.

Haven manages aircraft under both. Owners who only fly privately stay Part 91. Owners who want to reduce their cost of ownership can place their aircraft on Haven’s ARGUS Gold-rated Part 135 certificate through the Charter Back Offset program. There is no single right answer — it depends on how much you fly, how much control you want, and your appetite for charter activity on your aircraft.