Airline Medical Clearance and Certificate Rules (14 CFR 382.133)

Under federal law, an airline can only require medical clearance from a passenger with a disability in four narrow situations, and outside those situations asking for a doctor’s letter is a violation of the Air Carrier Access Act.¹ The airline medical clearance rules live in 14 CFR 382.23, which spells out when a certificate is allowed, what it must say, and how recent it must be.² Get the wrong kind of letter, or a letter dated outside the window, and you can be turned away at the gate even though your condition is entirely manageable.

The Four Situations Where an Airline Can Ask for a Certificate

A visible disability, a wheelchair, a service animal, or a condition that simply makes other passengers curious is not grounds for a medical certificate request. The regulation permits a certificate only in these cases:²

You are traveling on a stretcher or in an incubator.
You need supplemental oxygen supplied by the carrier during the flight.
Airline personnel have a reasonable basis to believe your condition could require extraordinary medical intervention mid-flight.
You have a communicable disease or infection that could pose a direct threat to other passengers or crew.

Any certificate request outside these four categories is not permitted under the regulation. An airline cannot require paperwork because a disability affects your appearance or behavior in ways that other passengers might find uncomfortable.³

What the Certificate Has to Say

There are two versions of the certificate, and they contain different statements. Bringing the wrong one is the most common reason paperwork is rejected at the gate.

Safe-Flight Certificate

If the trigger is stretcher use, an incubator, carrier-supplied oxygen, or concern about completing the flight safely, the certificate must be a written statement from your physician confirming that you can complete the flight safely, without requiring extraordinary medical assistance during the flight. “Extraordinary” means something beyond the basic first-aid equipment and training the flight crew already has. The document must be dated within 10 days of your initial departing flight.²

Communicable Disease Certificate

If the trigger is a contagious illness, the physician’s statement has to do a different job. It must say the disease or infection would not be transmissible to other people during the normal course of the flight given your current condition, and it must list any specific precautions needed to prevent transmission in the cabin. This certificate must also be dated within 10 days, but the window runs from the date of the specific flight rather than the initial departure.²

That distinction matters on multi-leg itineraries. A certificate dated nine days before your outbound flight can satisfy the safe-flight requirement for the whole trip, but a communicable disease certificate covering a connecting flight two weeks later would need to be reissued.

A Valid Certificate Doesn’t End the Conversation

Producing the correct letter does not automatically clear you to board. If the airline has a legitimate medical reason to believe your condition has worsened since the certificate was issued, or that the certificate significantly understates the risk to others, the carrier can require an additional medical review.² If that review concludes you cannot safely make the flight, or that you pose a direct threat to others, the airline can refuse boarding even with a physician’s letter in hand.

“Direct threat” is a defined term: a significant risk to the health or safety of others that cannot be eliminated by changing policies, procedures, or by providing auxiliary aids.⁴ The airline cannot apply that label in the abstract. It has to run an individualized assessment looking at the nature, duration, and severity of the risk, how likely harm actually is, and whether any reasonable accommodation would reduce the risk enough to allow you to travel.³ Full denial of boarding is only permitted when no lesser measure would work. For communicable diseases, carriers can rely on public health guidance from bodies like the CDC or the World Health Organization when they make that call.⁵

Bringing Your Own Respiratory Device Is a Separate Track

Documentation for a portable oxygen concentrator, ventilator, respirator, or CPAP machine is governed by 14 CFR 382.133, not by the general certificate rule. This is a separate paperwork requirement, and it applies even when none of the four situations above are triggered.

U.S. airlines operating aircraft with more than 19 seats must allow these devices in the cabin, provided the device meets FAA requirements and can be safely stowed.⁶ For portable oxygen concentrators specifically, you must present a physician’s statement to the airline at the airport, and the airline is required to inform you of that requirement during booking. The carrier can also require you to bring enough fully charged batteries to power the device for at least 150 percent of the expected maximum flight duration, calculated from the battery manufacturer’s run-time estimate and information from your physician’s statement about your usage needs.

If you show up without the required documentation or batteries, the airline can deny boarding under 14 CFR 382.19(c) and must give you a written explanation.⁶

Advance Notice for Oxygen and Incubators

Certain services trigger advance-notice rules that go alongside the certificate.⁷

Carrier-supplied medical oxygen on international flights: up to 72 hours’ notice, plus check-in one hour before the general boarding time.
Carrier-supplied medical oxygen on domestic flights: up to 48 hours’ notice, plus the same one-hour early check-in.
Incubator transport: up to 48 hours’ notice, plus one-hour early check-in.

Carrier-supplied oxygen and incubator transport are optional services. Airlines are allowed to provide them but are not required to, so confirm availability before you book. If you are bringing your own portable oxygen concentrator rather than using carrier-supplied oxygen, the 382.133 rules above apply instead.

Getting the Paperwork Right the First Time

Call the airline’s medical desk or special assistance department first and ask whether they have a proprietary form. Many carriers do, and their reviewers move through their own forms faster because they know where each required statement sits on the page. A letter on your physician’s letterhead is legally sufficient, but it needs to contain the exact language for your situation.

For a safe-flight certificate, the letter must confirm you can complete the flight without requiring extraordinary medical help. For a communicable disease certificate, it must state the condition will not be transmissible under flight conditions and list any necessary precautions. If both apply to you, both statements need to appear. A letter that only addresses one when both are needed will be rejected.

Watch the 10-day window. If you book a trip more than 10 days out, schedule the physician visit close to departure rather than at booking. For multi-leg trips, confirm whether the clock runs from initial departure or from each segment. Make sure the physician signs the letter legibly and includes contact information the airline can use to verify. Carry multiple copies, especially if you’re connecting through different carriers.

If You’re Turned Away at the Gate

When an airline refuses to let you fly for a disability-related reason, the carrier must provide a written statement explaining the specific basis for the decision and why the refusal is permitted under the regulation. If the statement isn’t handed to you at the airport, the airline must send it within 10 calendar days.³ Get this in writing every time. It becomes your primary evidence for any later complaint.

Every airline operating aircraft with 19 or more seats must have a Complaints Resolution Official available at each airport, either in person or by phone at no cost to you.⁸ Ask for the CRO by name if gate agents can’t resolve the issue. The CRO can overrule any other airline employee’s decision, with one exception: the CRO cannot countermand the pilot-in-command on a safety call. If you are still on the ground and no violation has occurred yet, the CRO must take whatever action is needed to bring the airline into compliance. If a violation has already occurred, the CRO must give you a written summary of what happened and what the airline plans to do, and must tell you about your right to file a complaint with the Department of Transportation.

Formal complaints go to the DOT’s Aviation Consumer Protection Division, which accepts submissions through its online form.⁹ DOT can issue cease-and-desist orders and civil penalties against the airline, but it cannot award you money damages. For financial compensation, such as rebooking fees or missed reservations, you would need to pursue a private lawsuit.