Two private jets can look identical on the ramp. Same model, same paint, same leather. One may be operating under rules built for commercial passenger service. The other may be operating under rules built for an owner flying themselves, their family or their company. If you are paying for the flight, the difference matters a great deal.
This is a plain guide to the two sets of rules, what they mean for passengers, and how to check which one you are flying under.
Two rulebooks
Part 91 of the federal aviation regulations covers general operating rules. It is the rulebook for private flying: an owner flying their own aircraft, a company flight department moving its employees, a pilot taking friends somewhere for the weekend. The FAA describes Part 91 as applying to private flights flown for personal purposes rather than commercial ones 1.
Part 135 governs commuter and on-demand operations, which is where most private charter sits. The FAA notes that these operations demand a higher level of pilot training and certification, maintenance procedures and safety rules 1. An operator must hold an FAA air carrier or operating certificate, and each aircraft it flies for hire must be authorized on that certificate.
The dividing line is compensation. NBAA puts it directly: Part 91 operators are barred from carrying passengers for compensation or hire, with few exceptions, and those who want to carry paying passengers must obtain an air carrier certificate and operate under Part 135 4.
The aircraft on the ramp may look the same. The rules behind it do not.
What the extra rules cover
Part 135 adds requirements in several areas that matter to passengers. Pilot training and checking are more structured. Maintenance follows defined programs. Operators are under ongoing FAA surveillance, and the agency has described Part 135 standards as including enhanced pilot training, structured maintenance programs and duty-time limitations 6.
Crew rest is a good example. For unscheduled Part 135 operations, a one-pilot crew is generally limited to eight hours of flight time in 24 hours and a two-pilot crew to ten, and pilots must have at least ten consecutive hours of rest in the 24 hours before the planned end of an assignment 5. Those limits are written into the Part 135 rulebook itself, which is part of why the FAA treats paid charter differently from private flying 1. That does not make every Part 91 flight unsafe. It means the passenger paying for a trip is entitled to the commercial standard.
Insurance is the other practical difference. NBAA notes that Part 135 carriers are subject to required insurance, and that when a flight sold for compensation is flown illegally under Part 91, insurers may deny claims and aircraft owners may face policy cancellation 3.
Illegal charter and how it is disguised
The FAA and industry groups use the term illegal charter, sometimes called gray charter, for flights sold to paying passengers but flown without Part 135 authority. The FAA warns that these operations can be presented as flight sharing, air sharing, time sharing, leasing or pool arrangements 2. The label alone does not settle the question. What matters is whether the operator holds the authority to carry paying passengers 4.
NBAA lists several warning signs: separate invoices for the aircraft and the pilots on a single trip, no federal excise tax on the bill, a price well below other quotes, being coached on what to tell an FAA inspector, and unrelated passengers from different companies on the same flight 3. The FAA’s own checklist asks passengers whether they were coached on what to say, whether they confirmed that both the aircraft and the operator are authorized, and whether they have taken on liability for the flight through operational control 1.
The consequences reach beyond the operator. NBAA notes that past cases have ended in certificate revocation and prison sentences, along with tax and customs exposure 3. The FAA reports that it has levied more than $18 million in penalties against rogue operators 1.
How to verify an operator
Verification takes a few minutes. The FAA’s advice is simple: when paying for an air charter, ask to see the operator’s air carrier or operating certificate 2. Then check it. The FAA publishes a searchable list of all FAA-certificated air charter operators on its Safe Air Charter site 1, and in 2026 it expanded that resource so passengers and brokers can confirm whether both a company and a specific aircraft are approved for charter 6. At the time of writing, the FAA lists 1,837 Part 135 certificate holders operating 11,582 authorized aircraft 1.
If you book through a broker, ask who the operating carrier is and check that company, not the broker. Suspected illegal operations can be reported to the FAA hotline at 1-866-835-5322 or hotline.faa.gov 1, or to the Air Charter Safety Foundation hotline, 888-SKY-FLT1, which NBAA notes is operated on behalf of the FAA 4.
Independent safety audits
Beyond the FAA certificate, many charter operators choose to be audited by independent safety organizations. These audits are voluntary, and they review how an operator runs its safety program, training, maintenance and history against a published standard.
ARGUS, for example, rates charter operators in tiers it calls Gold, Platinum and Platinum Elite, and describes its rating as evidence of adherence to an internationally recognized standard 8. Wyvern’s Wingman standard involves a two- to three-day on-site audit, followed by ongoing reporting requirements and continuous background checks on the operator, aircraft and crew 7. An audit rating is not a substitute for an FAA certificate. It is an additional, independent view of how seriously an operator takes safety, and it is reasonable to ask any operator which audits it holds and when they were last renewed.
What this means for you
When you pay for a private flight, three questions cover most of the risk. Who is the operating carrier? Is that carrier, and this aircraft, on the FAA’s list? Which independent audits does the operator hold? A legitimate operator answers all three without hesitation.
Aukeo Air flights are operated by FAA-certificated Part 135 carriers, disclosed before booking, and we are glad to share the operating carrier’s certificate details with any passenger who asks. This guide summarizes the rules for general understanding only, and flyers should confirm specifics with their own advisors or the FAA.
The aircraft on the ramp may look the same. The rules behind it do not.