Private or Commercial Flight: Part 91, Part 135 and EASA Rules

Whether a flight is private or commercial is not decided by the aircraft, the crew's uniforms or the price. It is decided by who holds operational control of the flight and whether passengers pay to be carried. In the United States the line runs between Part 91 and Part 135 of the federal aviation regulations. In Europe it runs between the non-commercial rules, Part-NCO and Part-NCC, and commercial air transport under an air operator certificate. The same jet can fly under either regime on consecutive days, which is why it is worth knowing which one your flight uses.

United States: Part 91

Part 91 contains the general operating and flight rules that apply to every flight in the US. For a private flight, it is essentially the whole rulebook. The operator, usually the owner or the owner's company, holds operational control, which the FAA defines as the authority over initiating, conducting or terminating a flight. Under Part 91 transport may not be sold to the public.

For large aircraft and multiengine jets, Subpart F allows a few narrow arrangements. A company may carry its own officials, employees and guests within the scope of its business. Under a time sharing agreement, the aircraft and crew may be provided to another person for a charge limited to listed costs, such as fuel, crew travel, landing fees and catering, plus an amount equal to the cost of the fuel. Interchange and joint ownership arrangements are also covered. Fractional ownership programmes fly under their own Subpart K.

Part 91 sets no crew duty limits and, for private flights, no take-off weather minimums. The take-off minimums written into Part 91 apply only to operators flying under Parts 121, 125, 129 and 135.

United States: Part 135

Part 135 governs on-demand charter and commuter flights. The operator holds a certificate issued under Part 119 with operations specifications from the FAA, and it holds operational control. Compared with a private flight, it adds layers:

• Minimum experience for captains: for flights under instrument rules, 1,200 hours as a pilot, including cross-country, night and instrument time.
• Regular checks, including an instrument proficiency check every six calendar months for captains flying under instrument rules.
• Flight time, duty and rest limits for crews.
• Weather rules for take-off and destination, and a drug and alcohol testing programme.
• A safety management system, with compliance declared to the FAA by 28 May 2027.

Europe: NCO, NCC, CAT and SPO

EU air operations rules (Regulation (EU) No 965/2012) sort flights by purpose and aircraft complexity.

• Part-NCO covers non-commercial flights with other-than-complex aircraft: piston aircraft, single turboprops, light helicopters and, by derogation, twin turboprops up to 5,700 kg.
• Part-NCC covers non-commercial flights with complex motor-powered aircraft. An aeroplane is complex if it has a maximum take-off mass above 5,700 kg, more than 19 passenger seats, a minimum crew of two pilots, or turbojet engines or more than one turboprop. That captures practically every business jet. The operator does not need a certificate, but must submit a declaration to its authority and keep a management system with safety management, an operations manual, a training programme and an approved minimum equipment list.
• Part-CAT covers commercial air transport, including charter, and requires an air operator certificate (AOC) and ongoing oversight by the authority. For aeroplanes, crews also work under the EU flight time limitation scheme.
• Part-SPO covers specialised operations, where the aircraft does a task such as filming or survey work rather than carrying passengers from A to B. It becomes relevant when a helicopter is hired for aerial filming at an event, for example.

The EU definition of a commercial operation is broad: any operation for remuneration or other valuable consideration that is available to the public or, if not, is performed under a contract where the customer has no control over the operator. Flying acquaintances for money is commercial even if it is never advertised. Non-EU charter operators flying into the EU also need a third country operator authorisation from EASA. The UK kept the same structure after leaving the EU.

Which rules apply to which flight

Type of flight	United States	EASA states
Private, light aircraft	Part 91	Part-NCO
Private or corporate, business jet	Part 91 (Subpart F, Subpart K for fractional)	Part-NCC, with a declaration
Charter	Part 135, certificate under Part 119	Part-CAT, with an AOC
Aerial work such as filming	Mostly Part 91	Part-SPO

Why the label matters

A private flight can be flown to a very high standard, and many corporate departments exceed what the rules demand. The difference is that on a commercial flight the standards are mandatory, approved and checked by a regulator. The label also decides liability and insurance. A policy written for private use may not respond if the aircraft is used for an illegal charter, which can leave passengers with nobody to claim against.

Illegal charter and how to spot it

Illegal or grey charter means a commercial flight dressed up as a private one. The FAA describes it as Part 91 flying that should be conducted under a Part 119 certificate, with sham leases and improper cost sharing as typical examples. Warning signs include:

• You pay for the flight, but nobody can give you an operator name and certificate number covering that aircraft.
• You are asked to sign a lease of the aircraft and to hire the pilots separately.
• You are told to describe yourself as a friend of the owner or an employee.
• The contract names the aircraft owner, not an operator, and the price is far below other quotes.

Our guides to choosing a charter operator and to brokers and operators show what to ask for in writing.

Questions

What is the difference between Part 91 and Part 135?

Part 91 contains the general rules for all flights in the United States and is the rulebook for private flights, where the owner or the owner's company holds operational control. Part 135 applies to charter: the operator needs an FAA certificate and must meet extra requirements on pilot experience, checks, crew duty limits, weather minimums and safety management.

Is it legal to share the cost of a private jet flight?

Only within narrow limits. In the United States, Part 91 allows time sharing and similar agreements for large aircraft and jets, with charges limited to specific costs. In Europe, the cost-sharing allowance for private individuals is limited to other-than-complex aircraft with no more than six people on board, so it does not extend to business jets.

How can I check that a charter flight is legal?

Ask for the name of the operator, its certificate or AOC number and confirmation that the aircraft is listed on it, and check with the issuing authority if in doubt. Be wary of being asked to lease the aircraft, to hire pilots separately or to say you are a friend of the owner.

Figures checked 19 October 2026. Prices are indicative and never a quote. Seen something out of date? Tell the editors.