What Does Part 135 Mean—and Why Should Passengers Care?

If you have spent any time researching private flights, you may have come across the phrase “Part 135 operator.” It appears on charter websites, in aircraft listings and in conversations throughout the aviation industry, usually without much explanation of what it actually means.

For passengers, however, it is an important distinction.

“Part 135” refers to the section of the Federal Aviation Regulations governing commuter and on-demand commercial air operations. In simpler terms, it is the regulatory framework under which companies like Capital Air Express are authorized by the Federal Aviation Administration to carry passengers for compensation as an air carrier. The FAA describes Part 135 as the authority used to operate on-demand, unscheduled air service, covering operators ranging from small single-aircraft companies to much larger organizations.

That may sound like an aviation technicality, but it has very practical implications for the person sitting in the passenger seat. When you pay someone to transport you by air, there is an important difference between simply hiring an airplane and pilot and flying with a certificated charter operator.

FAA Resource: Charter-Type Services (Part 135) — Federal Aviation Administration

Not Every Private Airplane Is a Charter Airplane

One of the easiest misconceptions to have about private aviation is that an aircraft available for private use can automatically be used for charter. That isn't the case.

A tremendous amount of general aviation in the United States operates under Part 91 of the Federal Aviation Regulations. Part 91 encompasses the general operating rules applicable to civil aircraft and includes many professionally operated privately owned aircraft. A business might own an airplane to transport its executives, for example, or an individual might own an aircraft for personal transportation.

The important distinction is that Part 91 is designed primarily for private operations, not commercial transportation of the public, and therefore does not carry the same level of FAA oversight and operational requirements that apply to Part 135 charter operators. The FAA specifically notes that charter operations require higher levels of pilot training and certification, aircraft maintenance procedures and operational safety rules than private flying, and that FAA inspectors perform more frequent checks of charter pilots, crewmembers and aircraft.

That does not mean a Part 91 flight is inherently unsafe; many Part 91 aircraft and professional flight departments operate to exceptionally high standards. It means those standards are not imposed and overseen through the same commercial regulatory framework that applies when an operator is being paid to transport passengers.

FAA Resource: Safe Air Charter — Federal Aviation Administration

What matters, then, is the nature of the operation. Once someone begins offering air transportation to the public for compensation, simply having an airplane and a commercially certificated pilot is not enough. The FAA specifically advises pilots that conducting air transportation requires both the appropriate pilot qualifications and compliance with the regulations applicable to the operation, such as Part 135. In other words, holding a commercial pilot certificate does not by itself authorize someone to start selling charter flights.

FAA Resource: Pilots, Owners and Operators — Safe Air Charter

This distinction can be surprisingly difficult for passengers to see. Two airplanes parked next to one another on the same ramp might look virtually identical. Both may be beautifully maintained, and both pilots may have extensive flying experience. But the regulatory framework governing how those airplanes are being operated may be very different.

That is why knowing who is actually operating your charter flight matters.

Part 135 Brings the FAA Into the Operation

A Part 135 certificate isn't simply a business license that an operator receives once and puts in a filing cabinet. The certification process requires an operator to demonstrate to the FAA how it intends to conduct its operation, and the resulting certificate is accompanied by specific operating authorizations and limitations.

Depending on the scope of the operation, Part 135 certification can involve company manuals, training programs, aircraft requirements, maintenance programs, drug and alcohol testing, management personnel and FAA-issued Operations Specifications. A standard Part 135 operator, for example, is required to maintain manuals and training programs and have designated management personnel. The FAA identifies positions including Director of Operations, Chief Pilot and Director of Maintenance for standard certificate holders.

FAA Resource: Part 135 Air Carrier and Operator Certification

The oversight continues after certification. According to the FAA's Safe Air Charter program, FAA inspectors perform more frequent checks on charter companies' pilots, crewmembers and aircraft than they do on private pilot operations, and charter crewmembers undergo regular proficiency checks.

For passengers, the important point isn't memorizing the regulations. It's understanding that a certificated charter flight is part of an established commercial aviation system with defined standards and federal oversight.

Commercial airlines operate under their own regulatory structure, primarily Part 121. On-demand charter operators typically operate under Part 135. They aren't identical systems, and their specific requirements differ, but both exist because carrying paying passengers is treated differently under federal aviation regulations than ordinary private flying.

Pilot Training Goes Beyond Having a Pilot's License

Passengers understandably tend to evaluate pilots based on experience: how many hours they have flown, how long they have been flying a particular aircraft or whether they fly professionally.

Those things matter, but Part 135 adds another layer.

The FAA states that air charter operations require a higher level of pilot training and certification than flights conducted by private pilots carrying family or friends. Part 135 operators must establish applicable training programs, and pilots must remain qualified for the operations they conduct. The FAA's consumer guidance also notes that charter crewmembers undergo regular proficiency checks.

FAA Resource: Safe Air Charter — Federal Aviation Administration

At Capital Air Express, our pilots are full-time W-2 employees rather than a rotating pool of contract pilots. That means our crews regularly fly within the same operation, under the same company procedures and in the same types of aircraft. We know our pilots personally, and they become deeply familiar with how we operate.

Pilots and other employees performing certain safety-sensitive functions in commercial aviation are also subject to federally required drug and alcohol testing programs. The FAA specifically points to drug and alcohol program requirements as part of the Part 135 certification framework.

FAA Resource: Part 135 Certification Requirements — Federal Aviation Administration

From the passenger's perspective, most of this is invisible. You see your pilots when you arrive at the airport; you don't see the training records, checking events, company procedures and regulatory systems behind them. But those systems are an important part of what distinguishes commercial charter operations from simply hiring someone who knows how to fly an airplane.

The Aircraft Is Part of the Certificate, Too

The same principle applies to the airplane.

An aircraft does not become an authorized charter aircraft simply because it is airworthy and insured. Aircraft used in a Part 135 operation must meet the applicable requirements and be authorized for use by that operator.

During certification and when aircraft are added to an operation, operators must demonstrate that the aircraft and its equipment conform to applicable requirements and are suitable for the intended operation. The FAA also states that, depending on aircraft complexity and the scope of the operation, maintenance requirements for Part 135 operations are more stringent than those for Part 91 operations.

FAA Resource: General Requirements for Part 135 Certification

At Capital Air Express, we take that framework further through our own maintenance practices. Our aircraft are maintained in-house by our sister company, Base Leg Maintenance, whose technicians work with these aircraft every day. In addition to the inspections and maintenance required for our operation, our team emphasizes proactive maintenance because reliability and safety are closely connected in a charter environment. Finding and addressing an issue in the shop is always preferable to discovering it when an aircraft is scheduled to carry passengers.

This is also why maintenance occasionally affects a customer's schedule. A charter aircraft is not simply dispatched because a trip is on the calendar. If an aircraft does not meet the standards required for the flight, it doesn't go until the issue is resolved.

That can be inconvenient when you're the passenger waiting to travel, but it is an important part of the system working as intended.

Part 135 Also Governs How Flights Are Operated

The regulations don't stop once the aircraft leaves the maintenance shop.

Part 135 contains operating requirements affecting how charter flights are conducted, while individual operators also operate according to their FAA-issued authorizations and company procedures. Together, those rules touch areas passengers may never think about, including crew qualifications, weather requirements, aircraft equipment, flight planning and crew flight-time and duty limitations.

This is one reason charter operators sometimes have to tell customers no.

A customer may reasonably look outside and see decent weather while the pilot is evaluating conditions at the destination, along the route and around possible alternate airports. A requested departure time may seem perfectly reasonable while creating a crew-duty issue once the entire day's flying is considered. An aircraft may appear completely normal while a maintenance discrepancy prevents it from being dispatched.

Good charter operations aren't built around finding ways around those limitations. They're built around recognizing them, communicating them and operating within them.

For customers accustomed to thinking of private aviation as completely unrestricted travel, that can require a small shift in perspective. Private charter gives you tremendous flexibility compared with scheduled airline travel, but it doesn't mean the rules disappear. The regulatory structure behind the flight is part of what separates commercial air transportation from ordinary private flying.

Part 135 and the Airlines: Different Operations, Similar Principle

We occasionally describe Part 135 as providing an airline-like level of regulatory oversight, and that can be useful shorthand as long as the distinction is understood.

Capital Air Express is not a scheduled airline. Airlines generally operate scheduled passenger service under Part 121, while our flights are on-demand and unscheduled under Part 135. The aircraft, routes, operating models and specific regulations are different.

The similarity is that both are forms of commercial air transportation conducted within FAA regulatory frameworks.

That matters because passengers sometimes compare a small charter aircraft with a privately owned airplane simply because they look similar. From a regulatory standpoint, the better comparison is between the type of operation being conducted.

A Piper operated privately by its owner and the same model Piper authorized to carry paying passengers for a Part 135 air carrier may look exactly the same sitting on the ramp, but the operation behind those airplanes is different.

For the passenger, that distinction is far more meaningful than the size of the aircraft.

What Part 135 Means at Capital Air Express

For Capital Air Express, operating under Part 135 shapes much more than what appears on our certificate. It influences how we hire and train pilots, how we maintain aircraft, how we document our operation and how we make decisions when a flight doesn't go exactly according to plan.

Our customers don't see most of that work, nor should they have to. Ideally, much of aviation safety is uneventful from the passenger's perspective. You arrive at the airport, meet your pilots, board the aircraft and go where you need to go.

Behind that simple experience, however, is a substantial amount of structure. There are trained and qualified pilots, aircraft authorized for commercial service, maintenance and operational records, company procedures, testing programs, FAA oversight and people whose jobs include making sure the operation continues to meet the standards attached to our certificate.

Those things aren't particularly glamorous, and most will never make it into a photograph of a private flight. They are, however, among the most important things a passenger is purchasing when choosing a legitimate charter operator.

The Question Worth Asking Before You Charter

Private aviation comes in many forms, from personally owned airplanes and corporate flight departments to aircraft management companies, charter brokers and certificated air carriers. From the outside, those distinctions aren't always obvious, particularly to someone who only flies privately a few times a year.

You don't need to understand every section of the Federal Aviation Regulations before booking a flight. But you should know who is responsible for operating your aircraft and under what authority the flight is being conducted.

The FAA itself makes the distinction fairly clear: charter operations require higher levels of pilot training and certification, aircraft maintenance procedures and operational safety rules than ordinary private flying. FAA inspectors also perform more frequent checks of charter pilots, crewmembers and aircraft than they do in private pilot operations.

That is ultimately what the words “Part 135” should mean to a passenger. You aren't simply purchasing access to an airplane and someone qualified to fly it. You're purchasing transportation from an air carrier operating within a defined commercial aviation framework for its pilots, aircraft, maintenance, procedures and federal oversight.

You may never need to think about any of that once you're sitting in the airplane. But it is worth knowing before you decide who you're going to fly with.