Direct Answer — DOT Economic Authority & Part 298
A Part 135 certificate is FAA safety authority — it approves how you fly. It is not economic authority and does not, by itself, let you hold out and sell air transportation. To carry passengers for compensation, a small-aircraft charter operator generally also needs DOT economic authority: registration under 14 CFR Part 298 as an air taxi operator, made by filing OST Form 4507 (Air Taxi Registration) in duplicate, together with a current certificate of insurance (OST Form 6410) and the filing fee (14 CFR 298.21). The statutory hook is 49 U.S.C. 41101, which requires a certificate to provide air transportation “except as provided in this chapter or another law” — and Part 298 is that exception for small-aircraft air taxis. You must keep liability insurance evidenced by a current certificate on file (14 CFR 298.37), with the dollar minimums set by 14 CFR Part 205. Bottom line: most charter operators need both the FAA Part 135 certificate and DOT Part 298 authority before flying revenue passengers.
Economic authority is fact-specific — confirm with DOT and counsel
Whether your operation needs Part 298 registration, a Commuter Air Carrier Authorization, or full certificate authority depends on your aircraft size and how you hold out service. This article explains the framework and the records side so you can operate transparently. It is not legal advice, and FileFlo does not represent you to the FAA or DOT, file your registration, opine on whether your structure is lawful, or guarantee any outcome. Before you sell a seat, verify the current rules and talk to a qualified aviation attorney.
How the Part 298 Registration Actually Works
Registration under Part 298 is a document filing with DOT, not a flight check. Here is the typical sequence. Note that none of this replaces your FAA Part 135 certification work — it sits alongside it, on the economic side.
Hold (or be obtaining) your FAA Part 135 certificate
Economic authority presupposes you are an air carrier the FAA has authorized to operate. The Part 298 registration form asks for your FAA certificate number, so the operating side is the foundation. For the FAA process itself, see our guide on how to get a Part 135 certificate.
File OST Form 4507 (Air Taxi Registration) in duplicate
Per 14 CFR 298.21(c), the 4507 identifies your carrier name and addresses, FAA certificate number, type of service, the aircraft you will use (registration numbers and capacity), proposed commencement date, and a U.S. citizenship certification. Filing the 4507 is what registers you as an air taxi operator for DOT purposes.
File a current certificate of insurance (OST Form 6410)
Under 14 CFR 298.37 you cannot operate unless liability insurance is in effect and evidenced by a current certificate of insurance on file with DOT, as required by Part 205. The 6410 is filed with your registration, and the minimum amounts come from 14 CFR Part 205.
Pay the filing fee
Part 298 registration carries a modest filing fee payable to the Department of Transportation (the regulation specifies the amount). It is an administrative fee, not a deposit or bond.
File at least 30 days before you commence operations
14 CFR 298.21(a) requires registration not later than 30 days prior to commencing operations. The registration then stays effective until you amend it or DOT cancels it (298.21(b)) — but your insurance certificate on file must stay current the entire time you operate.
The insurance piece, in plain English
The insurance requirement is where operators most often trip — not at first filing, but later, when a policy renews and the new certificate never makes it onto the DOT file. 14 CFR 298.37 is blunt: an operator “shall not operate in air transportation… unless there is in effect liability insurance which covers such transportation and which is evidenced by a current certificate of insurance on file with the Department as required by part 205.”
- The certificate is filed on OST Form 6410.
- The dollar minimums live in 14 CFR Part 205 and depend on operator type and aircraft — Part 205 sets per-passenger and third-party (members of the public) minimums, with lower thresholds available to U.S. air taxi operators using small aircraft and higher limits for larger operations.
- A lapse means you are no longer permitted to operate, even if your registration was never formally canceled.
Sources: 14 CFR 298.21, 298.37, 298.2, 298.3; 14 CFR Part 205 (minimum insurance amounts); 49 U.S.C. 41101. Verify the current filing forms, fee, and Part 205 dollar amounts against the official source — figures and procedures change, and the exact minimums depend on your operation. Confirm your specific filing with your insurer, DOT, and counsel.
A lapsed insurance certificate on file is an avoidable grounding
The OST-4507 registration data and the OST-6410 insurance certificate are exactly the kind of dated, must-stay-current documents that fall through the cracks. FileFlo keeps them organized, tracks the expiration, and makes the current version a search away. See where your records stand.
Related Aviation Compliance Guides
FAA Part 135 vs DOT Part 298: Side by Side
The clearest way to see why you need both is to put them next to each other. They answer different questions, are issued by different agencies, and fail in different ways.
| Dimension | FAA Part 135 certificate | DOT Part 298 registration |
|---|---|---|
| What it authorizes | How you may operate the aircraft (safety) | That you may hold out and sell air transportation (economic) |
| Regulator | Federal Aviation Administration (FAA) | U.S. Department of Transportation (DOT / OST) |
| Primary source | 14 CFR Part 135 | 14 CFR Part 298 (under 49 U.S.C. 41101 exemption) |
| How you obtain it | FAA certification process + operations specifications | File OST Form 4507 + certificate of insurance (OST 6410) + fee |
| Insurance role | Not the FAA certificate mechanism | Current certificate of insurance must stay on file (298.37; Part 205) |
| Aircraft scope (air taxi) | Per your ops specs / aircraft authorized | Small aircraft: 60 seats or fewer / 18,000 lbs payload or less |
| What a gap means | You are not safety-authorized to fly the operation | You are not economically authorized to sell the transportation |
They are not alternatives — they stack
The single most important takeaway: FAA Part 135 and DOT Part 298 are not two options you choose between. They apply at the same time to the same operator for different purposes. A charter operator who holds a Part 135 certificate but never registered under Part 298 — or whose insurance certificate on file has lapsed — has a real economic-authority gap, regardless of how clean the safety side is.
Air taxi operator vs commuter air carrier
Within Part 298 there are two flavors, divided by schedule frequency:
- Air taxi operator (14 CFR 298.3(a)): the classic on-demand charter case — small aircraft, no certificate of public convenience and necessity.
- Commuter air carrier (14 CFR 298.2, 298.3(b)): an air taxi operator carrying passengers on at least five round trips per week on at least one route, on published schedules — which also needs a Commuter Air Carrier Authorization.
That commuter-vs-on-demand line matters well beyond Part 298 — it shapes which FAA operating definitions apply. See Part 135 commuter vs on-demand for the operating-rule side.
This Is the Operator’s Authority — Not a Broker’s
A frequent and costly mix-up: confusing Part 298 (the operator’s economic registration) with 14 CFR Part 295 (the air charter broker rules). They cover different parties to the same transaction.
Air taxi operator (Part 298)
Holds an FAA certificate and actually flies the aircraft. Its economic authority is the Part 298 registration. It controls the operation, the crew, and the maintenance.
Operates the airplane · Part 298 registration · OST Form 4507
Air charter broker (Part 295)
Arranges and sells the trip but does not operate the aircraft. Defined in 14 CFR 295.5 as a person or entity that, as an indirect air carrier, foreign indirect air carrier, or bona fide agent, holds out, sells, or arranges single-entity charter using a direct air carrier.
Arranges the trip · Part 295 broker rules · Different duties
If you fly the airplane, your authority is Part 298 — not Part 295
The simple test: does your company actually operate the aircraft under an FAA certificate? If yes, your economic authority question is Part 298 (this guide). If you only source and sell charter to clients and contract the flying to someone else, you are on the broker side — see charter broker compliance under 14 CFR Part 295. Many companies do a bit of both, which is exactly when getting the distinction — and the records — right matters most.
This operator-vs-arranger distinction also drives the FAA’s enforcement focus on operational control — who is really directing the flight. When that line blurs, “grey charter” allegations follow. See the FAA crackdown on illegal “grey” charter and the related structural question of aircraft management company vs charter.
The Economic-Authority Records — and Where FileFlo Fits
Economic authority is, in the end, a document problem. The registration is paperwork; the insurance compliance is a certificate that must stay current on file. When DOT or the FAA asks whether you were authorized to sell and to fly, the answer is in your records. Here is the document set that proves your Part 298 economic authority, alongside the FAA operating records.
DOT economic authority (Part 298)
- OST Form 4507 air taxi registration (and any amendments)
- OST Form 6410 certificate of insurance — current on file
- Insurance policy + renewal documentation (Part 205 minimums)
- Commuter Air Carrier Authorization, if scheduled service
FAA operating authority (Part 135)
- Air carrier certificate & operations specifications
- Airman & medical certificates; training, checking, currency
- Aircraft airworthiness, maintenance, and AD compliance
- Operational control / flight-release & weight-and-balance
For the operating-side obligations in depth, see how to get a Part 135 certificate, and for the records-half discipline when a regulator comes asking, our guides on handling an FAA records request during an investigation and FAA fines for Part 135 paperwork violations. Because fractional and management structures get tangled up with charter economics, also compare Part 91K fractional ownership compliance records and the operating-rule overview in Part 91 vs Part 121 vs Part 135.
FileFlo: the Records Behind Your Economic Authority
FileFlo is a compliance document intelligence platform — the proof layer for your records. It does not file your Part 298 registration, represent you to the FAA or DOT, opine on whether your structure is lawful, give legal advice, run your safety program, or guarantee any outcome. Those belong to you, to DOT, and to a qualified aviation attorney. What FileFlo does is keep the document set that proves you were authorized to sell and to fly — current, complete, immutable, and instantly retrievable — so the OST-4507 registration data and the OST-6410 insurance certificate are a search away rather than a scramble.
- Classifies and indexes your DOT economic-authority documents (registration, insurance certificate, authorizations) alongside the FAA operating records
- Tracks the insurance-certificate expiration so a renewed policy actually lands on file — closing the 298.37 lapse gap before it grounds you
- Preserves an immutable, version-tracked history of every filing and amendment — the integrity that keeps a record set defensible
- Lets you produce everything for a specific aircraft, date range, and authority question in minutes
- Generates an inspector-ready, dated records index on demand, so a DOT or FAA request is answered, not feared
FileFlo classifies 600+ document types and manages records across Part 91, Part 135, and Part 145 operators. Pricing: Starter $89/mo, Professional $299/mo. 5-day free trial, no credit card required. FileFlo keeps the documents that prove compliance audit-ready — it is not an SMS, a dispatch/flight-operations system, an attorney, or a guarantee of any FAA or DOT outcome.
Frequently Asked Questions
Do I need DOT authority for Part 135?
In almost every case, yes. A Part 135 certificate is FAA safety authority — it says the FAA has approved how you fly. It does not, by itself, give you the economic authority to hold out and sell air transportation. For a typical on-demand air taxi using small aircraft, that economic authority comes from registering with the U.S. Department of Transportation under 14 CFR Part 298 (filing OST Form 4507, the Air Taxi Registration) and having a current certificate of liability insurance (OST Form 6410) on file as required by 14 CFR Part 205. 14 CFR 298.21(a) says an air taxi operator who plans to commence operations "shall register with the Department not later than 30 days prior to the commencement of such operations." So most charter operators need both pieces — the FAA Part 135 certificate and DOT Part 298 economic authority — before carrying passengers for compensation. Whether your specific operation needs Part 298 versus full certificate authority is fact-specific; confirm with DOT and a qualified aviation attorney.
What is Part 298 air taxi registration?
14 CFR Part 298 is a U.S. Department of Transportation economic regulation that exempts qualifying "air taxi operators" and "commuter air carriers" using small aircraft from the requirement to hold a full certificate of public convenience and necessity — provided they register with DOT and maintain the required insurance. Under 14 CFR 298.3(a), an air taxi operator is an air carrier that does not directly or indirectly use large aircraft and does not hold a certificate of public convenience and necessity. To use that exemption, you register by filing OST Form 4507 (Air Taxi Registration) in duplicate, file a certificate of insurance (OST Form 6410), and pay the filing fee, per 14 CFR 298.21(c). In plain English: Part 298 is the economic license that lets a small-aircraft charter operator legally sell transportation, sitting on top of — not instead of — the FAA Part 135 safety certificate.
What is OST Form 4507?
OST Form 4507 is the Air Taxi Registration form an operator files with the U.S. Department of Transportation to register for the Part 298 economic exemption. Under 14 CFR 298.21(c), it is filed in duplicate and typically identifies the carrier's name and addresses, its FAA certificate number, the type of service offered, the aircraft to be used (registration numbers and capacity), the proposed commencement date, and a certification of U.S. citizenship. Filing the 4507 is what "registers" you as an air taxi operator for DOT economic-authority purposes. It is filed together with a certificate of insurance (OST Form 6410) and the filing fee. The 4507 is a DOT economic document — it is separate from, and additional to, your FAA Part 135 certificate and operations specifications.
Why is a Part 135 certificate not enough to fly charter?
Because U.S. aviation law splits two questions that people often blur together: under what safety rules may the aircraft be flown (FAA operating authority), and who is allowed to hold out and sell air transportation (DOT economic authority). A Part 135 certificate answers the first. 49 U.S.C. 41101 answers the second — it provides that an air carrier may provide air transportation only if it holds a certificate "except as provided in this chapter or another law." That exception is the doorway to the Part 298 exemption: instead of a full certificate of public convenience and necessity, a small-aircraft air taxi registers under Part 298. So flying charter for compensation generally requires both the FAA Part 135 certificate and DOT economic authority (Part 298 registration plus the required insurance filing). Holding one without the other leaves a gap a regulator can act on.
What insurance is required for a Part 298 air taxi?
Under 14 CFR 298.37, an air taxi operator or commuter air carrier "shall not operate in air transportation or provide or offer to provide air transportation unless there is in effect liability insurance which covers such transportation and which is evidenced by a current certificate of insurance on file with the Department as required by part 205." The certificate of insurance is filed on OST Form 6410. The actual minimum dollar amounts live in 14 CFR Part 205, and they depend on the type of operator and aircraft — for example, Part 205 sets per-passenger and third-party (members of the public) minimums, with lower thresholds available to U.S. air taxi operators using small aircraft and higher limits for larger operations. Because the figures and how they apply to your fleet are specific, verify the current Part 205 amounts and your filing with your insurer, DOT, and counsel — do not rely on a remembered number.
What is the difference between an air taxi operator and a commuter air carrier?
Both are defined in 14 CFR Part 298 and both use small aircraft, but the dividing line is schedule frequency. Under 14 CFR 298.3(a), an air taxi operator is an air carrier that does not use large aircraft and does not hold a certificate of public convenience and necessity — the classic on-demand charter case. Under 14 CFR 298.3(b) and 298.2, a commuter air carrier is an air taxi operator that carries passengers on at least five round trips per week on at least one route, on published flight schedules specifying the times, days, and places. A commuter air carrier needs a Commuter Air Carrier Authorization in addition to registration. "Small aircraft" for these purposes means an aircraft originally designed for a maximum of 60 passenger seats or 18,000 pounds payload or less (14 CFR 298.2). If your scheduled service grows beyond those bounds, different — and more demanding — authority may be required.
Is Part 298 the same thing as charter broker registration under Part 295?
No — and confusing them is a common and costly mistake. Part 298 is the economic authority for the operator — the air carrier that actually holds an FAA certificate and flies the aircraft. 14 CFR Part 295 governs air charter brokers: a person or entity that, as an indirect air carrier, foreign indirect air carrier, or bona fide agent, holds out, sells, or arranges single-entity charter air transportation using a direct air carrier. A broker arranges and sells the trip but does not operate the aircraft; an air taxi operator operates the aircraft. They are different roles with different DOT obligations. If you are the one flying the airplane under a Part 135 certificate, your economic authority is Part 298 registration — see our companion guide on charter broker compliance under 14 CFR Part 295 for the other side of the transaction.
How long does DOT air taxi registration take and how long does it last?
Under 14 CFR 298.21(a), an air taxi operator must register "not later than 30 days prior to the commencement" of operations — so the practical answer is that you file well before you intend to start flying revenue trips, and the 30-day window is a floor, not a target. Once accepted, the registration remains effective until the carrier amends it or DOT cancels it (14 CFR 298.21(b)) — there is no fixed annual renewal of the registration itself the way some licenses work. That said, your obligation to keep a current certificate of insurance (OST Form 6410) on file under 14 CFR 298.37 is continuous: if the insurance lapses or the certificate on file goes stale, you are no longer permitted to operate, even though your registration was never formally canceled. Keeping the insurance filing current and your registration data accurate is exactly the document-discipline problem FileFlo is built for.
Two authorities, two record sets. Be ready to prove both.
A charter operator answers to the FAA on the safety side and DOT on the economic side. FileFlo keeps your aviation records — including the OST-4507 registration data and the OST-6410 insurance certificate — current, complete, immutable, and instantly retrievable, and documents corrective action, so when a regulator asks, the records are a search away. FileFlo does not file your registration, represent you to the FAA or DOT, give legal advice, or guarantee an outcome — it produces and proves your records. Starter plan $89/mo. Professional $299/mo. 5-day free trial — no credit card required.
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Written by Chad Griffith, Founder, FileFlo — compliance document intelligence. Reviewed June 15, 2026. This article is general compliance document information, not legal advice. A charter operator generally needs both FAA safety authority (a 14 CFR Part 135 certificate) and DOT economic authority (registration under 14 CFR Part 298 via OST Form 4507, with a current certificate of insurance on file under 14 CFR 298.37 and the minimums in 14 CFR Part 205); the statutory certificate requirement and its exemption are at 49 U.S.C. 41101. Whether your specific operation needs Part 298 registration, a Commuter Air Carrier Authorization, or full certificate authority is fact-specific — consult a qualified aviation attorney and verify every regulation, form, fee, and dollar amount against the current source.