Direct Answer
Part 91 vs Part 135 turns on one question: are you conducting common carriage for compensation or hire? If you are holding out to the public a willingness to carry passengers or cargo from place to place, and value of any kind flows to you for it, you are almost certainly in Part 135 territory and 14 CFR Part 119 generally requires you to hold a certificate. The aircraft and your pilot rating do not decide it — the nature of the operation does.
The FAA’s test for common carriage (from Advisory Circular 120-12A guidance) has four elements: (1) a holding out of a willingness to (2) transport persons or property (3) from place to place (4) for compensation or hire. Two of those — “holding out” and “compensation” — are construed far more broadly than most pilots expect, which is why operators cross the line without realizing it.
This is a legal characterization, not a documentation one. Whether a specific flight is Part 91 or Part 135 is a determination for an aviation attorney. FileFlo does not make that call. What FileFlo does is the records work that starts the moment you operate under Part 135 — keeping the pilot, training, maintenance, manual, and authorization records audit-ready.
It’s the Operation, Not the Airplane
The single most common misconception about the Part 91 / Part 135 line is that it is about equipment — that a bigger or faster aircraft is “a Part 135 airplane” and a smaller one is “a Part 91 airplane.” It is not. The same Pilatus PC-12 or King Air can be flown perfectly legally under Part 91 one day and require a Part 135 certificate the next. What changed is not the aircraft — it is whether the operation is common carriage for compensation or hire.
The applicability rule lives in 14 CFR §119.1. It reaches persons operating as an air carrier or commercial operator in air commerce, and — importantly — it also reaches noncommon carriage and private carriage for compensation in aircraft with a passenger-seat configuration of fewer than 20 seats and a payload capacity of less than 6,000 pounds. Cross 20 seats or 6,000 pounds payload, and you are generally pushed toward Part 121. The point for most charter-scale operators is simple: if you are carrying people or cargo for compensation in a typical business aircraft, §119 almost certainly applies, and Part 135 is where you live.
Part 91, by contrast, is the general operating-rules home for flying that is not for-hire commercial carriage — your own business or personal transportation, training, and a set of specifically defined operations. The trap is the gray zone in between, where a Part 91 operator starts doing favors, sharing costs, or accepting value that quietly satisfies the “compensation” element while a reputation for “flying anyone who calls” quietly satisfies “holding out.” That is exactly the territory the FAA polices as illegal or “grey” charter.
This is a legal question — defer it to counsel
The Part 91 / Part 135 boundary has been litigated and interpreted for more than 30 years, and the outcomes are fact-specific. Nothing here is legal advice. If there is any chance your operation involves carrying others for value, get a written determination from a qualified aviation attorney before the flight — not after an FAA inquiry. FileFlo is the records layer for operators who already know which rules apply; it does not assess your operation or render legal opinions.
Once you know you are on the Part 135 side of the line, the practical questions shift to certification and recordkeeping — see how to get a Part 135 certificate, what operational control means, and the FAA’s grey-charter crackdown.
The Four-Element Common-Carriage Test
The FAA does not define “common carriage” with a single bright-line number in the CFR. Instead it uses a four-element test set out in Advisory Circular 120-12A, “Private Carriage Versus Common Carriage of Persons or Property.” This is FAA guidance — the agency’s and the courts’ framework for applying the statute — not regulatory text you will find numbered in Part 119. Under that guidance, a person is engaged in common carriage when there is:
Element 1 — A holding out
A holding out, by any means, of a willingness to transport persons or property to the public — or to a segment of the public. This is the element operators most often satisfy without intending to. You can hold out by reputation or course of conduct, not just advertising.
Element 2 — To transport persons or property
The activity is the transportation of passengers or cargo. Carrying people or things is the core service being offered — as opposed to, say, instruction or aerial work where carriage is incidental to a different purpose.
Element 3 — From place to place
The transportation moves persons or property from one place to another. Point-to-point carriage is the ordinary charter profile; this element is rarely where the analysis turns.
Element 4 — For compensation or hire
Compensation or hire is involved. Under FAA guidance this is read very broadly — it does not require profit, and value other than cash (flight time, goodwill, reimbursed expenses) can qualify. This is the second element that catches operators by surprise.
Guidance, not a CFR section
The four-element test is the FAA’s explanatory guidance in AC 120-12A and the body of legal interpretation around it — not a numbered rule in the CFR. The hard regulatory anchor is 14 CFR §119.1, which determines who must hold a certificate. When all four elements are present, the operation is common carriage and §119 generally pulls it under Part 135 (or Part 121 for larger aircraft). Whether the elements are met in your case is a legal determination — bring it to aviation counsel.
Common carriage vs. private (contract) carriage
The mirror image of common carriage is private carriage (sometimes called contract carriage): carriage for hire that does not involve holding out. FAA guidance describes private carriage as service to one or a small number of selected customers, generally under contract, where the number of customers is small enough that it does not suggest a willingness to contract with anybody who asks. It is a question of degree — a few long-term contracts can be private carriage, while carriage under many contracts starts to look like common carriage regardless of the label on the paperwork.
The critical thing operators miss: private carriage for compensation can still require a Part 119 certificate and Part 135 operation. §119.1 expressly reaches noncommon carriage and private carriage for compensation in aircraft under 20 seats and under 6,000 pounds payload. “It’s private carriage” is not a defense to operating without a certificate — it changes the analysis, not necessarily the outcome.
For the structural questions that ride alongside this — who actually controls the flight, and how leases interact with the line — see what operational control means in Part 135 and truth-in-leasing aircraft lease records (§91.23), since a “dry lease” that does not really transfer operational control is a classic illegal-charter structure.
“Holding Out”: The Element That Trips Everyone
If there is one concept to internalize from this entire article, it is holding out. FAA guidance describes a carrier as holding out when it communicates to the public — or any segment of the public — a willingness to furnish air transportation to anyone who wants it, within the limits of its facilities. Holding out is the element that converts an otherwise-private arrangement into common carriage, and it is the one operators satisfy by accident.
The dangerous part is how many ways you can hold out without ever buying an advertisement. FAA guidance recognizes that holding out can happen through any of these channels:
Advertising & solicitation
The obvious one: ads, a website offering flights to the public, social posts soliciting passengers, signs, or listing your aircraft on a charter marketplace. If the public can see an offer to fly them, you are holding out.
Reputation
FAA guidance is explicit that physically holding out — without any advertising — where a pilot gains a reputation of serving all comers is enough. Word-of-mouth that you will fly anyone who calls is holding out.
Course of conduct
A pattern of accepting whoever asks, over time, can constitute holding out even with no single advertisement and no formal offer. The behavior speaks louder than the marketing.
Through an agent or broker
Holding out can occur through a third party — a broker, a booking agent, or an arrangement that markets your aircraft to the public on your behalf. You can hold out without doing the advertising yourself.
You cannot contract your way out of holding out
Operators sometimes believe a cleverly drafted “membership,” “club,” or “dry lease” structure makes holding out disappear. It does not — the FAA looks at substance over form. If the practical reality is that you are willing to fly whoever shows up with money, the label on the agreement will not save you. Whether your specific arrangement involves holding out is a fact-specific legal question for aviation counsel, full stop.
Holding out through a broker is precisely why charter intermediaries are regulated too — see charter broker compliance under 14 CFR Part 295. And because so many illegal-charter cases hinge on holding out plus a sham lease, the FAA’s grey-charter enforcement is worth understanding in detail.
“Compensation or Hire” Is Broader Than You Think
The fourth element — compensation or hire — is the other place operators trip, because they equate “compensation” with “profit” or even “cash.” FAA interpretations have consistently read it far more broadly. Compensation does not require a profit, and it does not require money to change hands at all. What matters is whether something of value flows to the operator or pilot in exchange for the transportation.
FAA legal interpretations have treated the following as compensation in various contexts:
Accumulation of flight time
Building logged hours can itself be compensation — the value is the experience and the hours, even if no one paid a dime. This has tripped up pilots who thought free flying for the logbook was harmless.
Reimbursement of expenses
Being reimbursed for fuel, costs, or operating expenses can constitute compensation. The narrow private-pilot cost-sharing allowances are an exception with strict conditions — not a general rule that reimbursement is free of consequence.
Goodwill and business benefit
Carrying customers, prospects, or business contacts to generate goodwill or further a business can be compensation even when the passengers pay nothing directly — the value to the operator is the business benefit.
Non-cash value of any kind
The broad principle is that compensation is not limited to a fare. If value moves to the operator in connection with the carriage, the compensation element may be satisfied regardless of its form.
Why “we weren’t making money” is not a defense
Because compensation does not require profit, the common protest — “but we were just covering costs” or “nobody made any money” — is not, by itself, a defense to operating without a certificate. The breadth of the compensation element is exactly why so many well-intentioned arrangements turn out to be commercial operations. The specifics of what counts as compensation in your facts are a determination for an aviation attorney; do not rely on a general article — including this one — for that call.
Put holding out and broad compensation together and you see why the line is so easy to cross unintentionally: a pilot who develops a reputation for flying business contacts “to build hours” may satisfy both the holding-out element (reputation/course of conduct) and the compensation element (flight time and goodwill) without ever buying an ad or charging a fare.
Once you operate under Part 135, can you prove it on demand?
FileFlo does not decide whether your flight is Part 91 or Part 135, and it does not give legal advice — that is your aviation attorney’s job. What it does is the records work that begins the moment you operate as a certificated Part 135 operator: classifying, version-controlling, and tracking expirations on your pilot, training, maintenance, manual, and OpSpecs records so they are audit-ready, not reconstructed in a panic. Starter at $89/mo, Professional at $299/mo. 5-day free trial, no credit card required.
The Part 91 Carve-Outs (and Their Limits)
There are genuine, defined situations where flying for value, or flying operations that look commercial, stays under Part 91. They are narrow, technical, and frequently misread as broader than they are. Two sets matter most.
1. Operations §119 simply does not apply to
14 CFR §119.1(e) lists operations to which Part 119 does not apply — meaning they are not pulled into the air-carrier/operating-certificate framework even though some involve compensation. These include:
Note what this list is and is not. It is a set of specific aerial work and instructional/ferry operations Congress and the FAA carved out — not a general permission to carry passengers point-to-point for money. None of these is a path to running charter under Part 91. Banner towing is not a loophole for flying people to the Hamptons.
2. Part 91 Subpart F (§91.501) for large & turbojet aircraft
14 CFR §91.501 prescribes operating rules for large airplanes of U.S. registry, turbojet-powered multiengine civil airplanes of U.S. registry, and fractional ownership program aircraft. It allows certain operations to be conducted under Subpart F instead of Part 135 — but only the specific operations listed in §91.501(b), and (critically) these rules do not apply when the aircraft is required to be operated under Parts 121, 125, 129, 135, or 137. The listed operations include, among others:
Ferry or training flights
Repositioning and crew-training flights.
Company carriage incidental to business
Carriage of officials, employees, guests, and property of a company on company business, when the costs do not exceed what the rule allows.
Time-sharing, interchange, or joint-ownership agreements
Carriage conducted under these specifically defined agreements — each of which is a defined term with strict conditions and, for time-sharing and interchange, truth-in-leasing implications. These are not a generic "charter workaround."
Demonstration flights with no charge
Demonstrating an airplane to a prospective buyer when no charge is made (with limited exceptions).
Personal transportation with no charge
The operator carrying themselves or guests when no charge, assessment, or fee is made.
Subpart F is not a charter substitute
§91.501 carve-outs like time-sharing and interchange agreements are narrow, condition-laden, and a frequent setting for illegal-charter findings when the arrangement does not actually fit the defined category — or when operational control does not transfer the way the paperwork claims. They exist for genuine large-aircraft and company-flight situations, not as a way to sell seats to the public. Time-sharing and interchange agreements also trigger truth-in-leasing recordkeeping under §91.23. Treat any reliance on §91.501 as something to confirm in writing with aviation counsel.
For the lease side of these arrangements and why a paper “dry lease” can backfire, see truth-in-leasing aircraft lease records under §91.23, and for the people who must be in place once you are a certificated operator, see Part 135 required management personnel qualifications.
Crossing the Line Is an Enforcement Risk, Not a Technicality
The Part 91 / Part 135 line is not academic. The FAA actively pursues illegal “grey” charter — flights flown for compensation or hire outside a Part 119/Part 135 structure — and it has brought a series of enforcement actions against operators, including proposed civil penalties and emergency actions affecting certificates. Reported actions in recent years have included individual proposed penalties in the six figures, and the agency has publicly warned against both illegal charter and “sham” lease agreements used to disguise it.
We are deliberately not quoting a precise running total here, because those figures move and are often proposed rather than final. The durable point is the exposure: operating commercial carriage under Part 91 risks penalties, certificate action, and — just as important — insurance and liability problems, because an illegal-charter flight may fall outside coverage. The FAA also now requires a Safety Management System for Part 135 operators and certain air-tour operations, with a compliance deadline in May 2027, reinforcing that paid passenger-carrying flying is meant to run under organized oversight.
The hidden cost: insurance and liability
Beyond FAA penalties, flying an illegal charter can void insurance coverage and expose the operator and pilot to liability that a properly certificated operation would not face. An accident on an uncertificated for-hire flight is a worst-case scenario on every axis. This is one more reason the line is worth getting right with counsel before the flight.
Enforcement framing reflects FAA guidance and publicly reported enforcement activity; specific penalty figures are proposed and subject to change. For the SMS deadline, see the Part 135 SMS 2027 deadline and Part 135 SMS requirements.
After You Cross the Line: The Records That Prove You’re Compliant
Here is where the legal question hands off to a documentation one — and where FileFlo fits. The decision of whether you are Part 91 or Part 135 belongs to your aviation attorney. But once you are a certificated Part 135 operator, you carry a continuous obligation to prove compliance with current, organized, retrievable records. A surveillance inspector does not take your word that you are compliant; they ask to see the documents. These are the record families that matter, and how FileFlo keeps them audit-ready.
Pilot qualification & currency records
Part 135 pilot recordkeepingWhy it matters once you operate
Records establishing each required crewmember’s certificates, checks, and currency. A commercial certificate authorizes the pilot, but the operation must prove the crew is qualified and current for every flight it dispatches.
How FileFlo keeps it audit-ready
FileFlo classifies and tracks pilot qualification and currency records, surfacing expirations before they ground a flight.
Operating manuals — kept current
14 CFR §135.21Why it matters once you operate
The General Operations Manual (for operators using more than one pilot) must be prepared and kept current and used by the personnel who run the operation. A stale manual is a finding.
How FileFlo keeps it audit-ready
FileFlo version-controls each manual revision with effective dates and a retained history, so the live version is always identifiable and superseded ones never get mistaken for current.
Maintenance & airworthiness records
Aircraft maintenance recordkeepingWhy it matters once you operate
Inspection-program and continuous-airworthiness records for each aircraft must be complete and current — the evidence that the very same airplane that could fly Part 91 is now maintained to the operator’s approved program.
How FileFlo keeps it audit-ready
FileFlo indexes maintenance and inspection records against each tail number and program, keeping the airworthiness picture complete and retrievable.
OpSpecs & authorization documents
14 CFR §119.43Why it matters once you operate
Your operations specifications must be maintained and mirrored in your operating manual, and every authorization implies underlying evidence you still meet its conditions. The crossing from Part 91 to Part 135 is, in large part, the issuance of these OpSpecs.
How FileFlo keeps it audit-ready
FileFlo version-tracks OpSpecs revisions and links them to the manual excerpts and records that must stay in sync.
Related reading: What records a Part 135 operator must keep · Part 135 pilot records required by the FAA · Operations specifications (OpSpecs) explained · How to prepare for a Part 135 surveillance audit · Single-pilot operator records · General Operations / Maintenance Manual requirements
FileFlo is the records layer — not legal counsel and not the certification team
To be unambiguous: FileFlo is a compliance document intelligence platform that classifies, indexes, version-controls, and tracks expirations on your compliance documents. It does not decide whether your operation is Part 91 or Part 135, render legal opinions, obtain your certificate, file your application, write your manuals, broker any deal, or provide legal, financial, or tax advice. The Part 91 / Part 135 determination belongs to your aviation attorney; certification belongs to your certification team, your required management personnel, and your FAA Flight Standards office. Once you operate under Part 135, keeping the record that proves your compliance complete, current, and audit-ready is the document problem FileFlo solves. (FileFlo does not claim SOC 2 certification.)
Frequently Asked Questions
What is the difference between Part 91 and Part 135?
Part 91 is the FAA's general operating rule for private, non-commercial flying — you fly your own aircraft, or your company's, for your own purposes, and you do not hold yourself out to carry the public for compensation. Part 135 governs on-demand commercial operations: carrying passengers or cargo for compensation or hire when you are holding out to the public. The dividing line is not the size of the aircraft or whether you have a commercial pilot certificate — it is whether you are conducting common carriage for compensation. Once you cross that line, 14 CFR Part 119 generally requires you to hold an air carrier or operating certificate and run the flight under Part 135. FileFlo is the records layer once you operate under Part 135; it does not give legal advice, and whether a specific flight is Part 91 or Part 135 is a determination for aviation counsel.
What does "compensation or hire" actually mean in aviation?
Under FAA guidance, compensation is construed very broadly — it does not require profit, and it does not even require cash. FAA interpretations have treated the accumulation of flight time, the reimbursement of expenses, goodwill, and other indirect benefits as compensation. That is why so many operators are surprised to learn they have crossed into commercial territory: they were not making money, but value flowed to them in exchange for the transportation. The practical takeaway is that you cannot assume a flight is non-commercial just because no one paid a fare. If anything of value moves to you in connection with carrying someone, treat the compensation element as potentially met and get a legal determination. FileFlo does not make that determination — that is a question for your aviation attorney.
When do I need a Part 135 certificate?
As a general rule, you need to operate under Part 135 (and hold the certificate that 14 CFR Part 119 requires) when you are conducting common carriage of passengers or cargo for compensation or hire in smaller aircraft — generally aircraft with fewer than 20 passenger seats and a payload capacity under 6,000 pounds; larger aircraft push you toward Part 121. The FAA's common-carriage test (from Advisory Circular 120-12A guidance) has four elements: (1) holding out a willingness to (2) transport persons or property (3) from place to place (4) for compensation or hire. If all four are present, you are almost certainly in Part 135 territory. There are narrow carve-outs — student instruction, ferry and training flights, and certain aerial work like crop dusting, banner towing, aerial photography, and pipeline patrol are listed in 14 CFR §119.1(e) as operations Part 119 does not apply to — but those are specific exceptions, not loopholes for charter. Confirm your situation with aviation counsel; FileFlo is the documentation layer once you are operating, not a legal advisor.
Can I fly Part 91 and charge passengers for the flight?
Generally, no — not if you are holding out to the public and carrying passengers for compensation or hire. That combination is the definition of common carriage, and common carriage of passengers for hire in small aircraft is what Part 135 exists to regulate. Charging passengers a fare while operating under Part 91 is the classic profile of an illegal ("grey") charter, and the FAA has pursued enforcement actions and substantial proposed civil penalties against operators who do it. There are narrow Part 91 cost-sharing provisions for private pilots and specific Subpart F arrangements for large and turbojet aircraft (like time-sharing and interchange agreements under §91.501), but these are limited, technical, and heavily litigated — they are not a general license to charge for flights. Before you accept any payment for carrying someone, get a determination from an aviation attorney. FileFlo does not provide that advice; it organizes and proves your compliance records once you operate.
What is "holding out" and how do I avoid doing it accidentally?
Holding out, in FAA guidance, means communicating to the public — or any segment of the public — a willingness to furnish air transportation to anyone who wants it. The trap is that you do not have to advertise to be holding out. FAA guidance recognizes that you can hold out by reputation, by a course of conduct, through an agent or broker, or by physically being available to all comers, even with no advertisement at all. A pilot who develops a reputation for flying anyone who calls is holding out just as surely as one who buys ads. This is why the holding-out element is the single most common way operators stumble into commercial-operator status without realizing it. You cannot reliably avoid it with a clever contract or a private-sounding arrangement; whether you are holding out is a fact-specific legal question for aviation counsel. FileFlo does not assess holding out — it is the records layer for operators who already know which rules apply to them.
What is the difference between common carriage and private carriage?
Common carriage is holding out to the general public a willingness to transport anyone, for compensation. Private (or contract) carriage is carriage for hire that does NOT involve holding out — typically service to one or a small number of selected customers under contract, where the number is small enough that it does not suggest a willingness to contract with just anybody. FAA guidance (Advisory Circular 120-12A) frames this as a question of degree: a handful of long-term contracts may be private carriage, while carriage under many contracts can look like common carriage no matter how it is labeled. Crucially, private carriage for compensation in small aircraft can STILL require a Part 119 certificate and Part 135 operation — §119.1 expressly reaches noncommon carriage and private carriage for compensation in aircraft under 20 seats and under 6,000 pounds payload. "Private carriage" is not a synonym for "unregulated." These are legal characterizations best confirmed with an aviation attorney; FileFlo is the document-proof layer, not legal counsel.
Does having a commercial pilot certificate let me fly Part 135 charters?
No. A commercial or airline transport pilot certificate lets you act as a pilot for compensation, but it does not authorize you to conduct commercial passenger or cargo operations on your own. To fly for-hire common carriage, the operation itself must be conducted under an air carrier or operating certificate issued under 14 CFR Part 119, and the pilot must be operating as a direct employee or agent of that certificate holder — or hold the Part 119 certificate themselves. In other words, the certificate regulates the operator, not just the pilot. A commercially rated pilot who carries passengers for compensation outside a Part 119 / Part 135 structure is still flying an illegal charter. FileFlo does not certify pilots or operators; it keeps the pilot, training, and operating records that prove a certificated operation stays compliant.
How does FileFlo help with Part 91 versus Part 135 compliance?
FileFlo does not decide whether your flight is Part 91 or Part 135, write your manuals, file your certificate application, or interact with the FAA — those are jobs for your aviation attorney, your certification team, and your required management personnel. What FileFlo does is the records work that begins the moment you operate under Part 135. It is a compliance document intelligence platform that classifies, indexes, version-controls, and tracks expirations on the documents a certificated operator must keep: pilot qualification and currency records, training records, maintenance and airworthiness records, your manuals, and your OpSpecs and authorization documents. The legal line between Part 91 and Part 135 is a determination for counsel; once you are on the Part 135 side of that line, proving you are compliant — with current, organized, audit-ready records — is the document problem FileFlo solves. FileFlo does not provide legal, financial, or tax advice and does not claim SOC 2 certification.
Know which rules apply — then prove you follow them
The Part 91 / Part 135 line is a legal call for your aviation attorney. The day-to-day job of proving a certificated operation stays compliant is a records problem — and that is what FileFlo solves. It classifies, version-controls, and tracks expirations on your pilot, training, maintenance, manual, and OpSpecs records so they are audit-ready on demand. AI document classification. 600+ document types. One-click FAA surveillance binder. Starter at $89/mo, Professional at $299/mo. No credit card required for the 5-day free trial. FileFlo does not give legal advice or get you certified — it organizes and proves your compliance documents.
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Continue your Part 135 certification reading
Reviewed by Chad Griffith, Founder, FileFlo — compliance document intelligence. Last reviewed June 15, 2026. The applicability framework is verified against the Cornell Legal Information Institute eCFR (14 CFR §119.1 and §91.501). The four-element common-carriage test, the meaning of “holding out,” and the broad reading of “compensation or hire” reflect FAA guidance in Advisory Circular 120-12A and longstanding FAA legal interpretation — guidance, not regulatory text. Enforcement references reflect publicly reported FAA activity; specific penalty figures are proposed and subject to change. This article is a compliance-document perspective and is not legal, financial, or tax advice; whether any specific flight or arrangement is Part 91 or Part 135 is a determination for a qualified aviation attorney and your FAA Flight Standards office.