Part 91 vs Part 135: Why It Matters When You Charter a Jet

You ask for a private jet quote. The broker says the flight is "Part 135." Or the operator says "Part 91." What does that mean for you? The answer affects your safety, your insurance, and your legal risk.

This guide explains both rules in plain words. It is based on US rules from the FAA. Other countries use different names, but the idea is the same.

What is Part 91?

Part 91 is the basic set of flight rules in the United States. It covers how any aircraft must be flown. It applies to private flights. If a company flies its own staff in its own jet, that is usually a Part 91 flight. If you own a plane and fly your family, that is Part 91 too.

Part 91 flights are not sold to the public. The owner or operator cannot take money from passengers for the ride. There are narrow exceptions, such as certain cost sharing, time sharing, and interchange deals. These have strict rules.

What is Part 135?

Part 135 covers commuter and on-demand flights. This is what most people call charter. A company that sells seats or whole aircraft to the public must hold an FAA air carrier certificate. It must follow Part 135.

The rules are tougher than Part 91. Part 135 operators must meet rules on:

• Pilot training and regular check rides
• Pilot rest and duty time
• Aircraft maintenance programs
• Drug and alcohol testing
• Approved operating procedures

To get the certificate, an operator goes through a long FAA process. We cover it in our guide to the Part 135 certification process.

Part 91 vs Part 135 at a glance

Point	Part 91	Part 135
Who flies it	Owners and companies, for their own use	Air carriers selling flights to the public
Can passengers pay?	No, apart from narrow exceptions	Yes
FAA air carrier certificate	Not needed	Required
Crew training and checks	Basic rules	Stricter, with regular checks
Typical use	Private ownership, corporate flights	On-demand charter

What is illegal charter?

Illegal charter happens when someone sells a flight but does not hold the right certificate. The aircraft owner may fly you on a Part 91 plane and take payment for it. That is not allowed. The FAA has warned about this for years.

The risk is real for you. Insurance may not cover the flight. The crew may not have the training that a charter flight needs. If something goes wrong, you may have little protection.

How to check your operator

1. Ask for the operator's name and its FAA air carrier certificate number.
2. Ask for proof of insurance that covers passengers on charter flights.
3. Ask who is the operator of record for your flight. A broker is not the operator.
4. Ask for the aircraft registration number and check it matches the operator.
5. Be careful if the price is far below every other quote.

A good broker does this checking for you. See our guide on broker vs operator and how to choose a charter broker.

What about outside the USA?

In Europe, the term is Air Operator Certificate, or AOC. In the UK, the CAA issues it. Commercial flights need an AOC. Private flights by an owner do not. The same check applies: ask for the certificate, and ask who the operator is.

Where Part 91 is fine

Part 91 is not bad. It is the right rule for owners flying their own aircraft. Many large companies run their own flight departments under Part 91. The point is simple. If you are paying for a seat or a whole plane, the flight should be Part 135, or the local equal.

Find certified charter operators

Browse operators and brokers in our directory: Charter.

Sources: FAA, 14 CFR Part 91 and Part 135; FAA guidance on illegal charter operations; UK CAA and EASA air operator certificate pages.