Fit to fly certificates: what airlines actually require (and what they don’t).
Airlines do not routinely require a fit to fly certificate — but there are specific medical situations where one is mandatory, and others where it is strongly advised. Understanding exactly what your airline needs, and when, prevents being denied boarding. This guide explains the rules clearly.
What Is a Fit to Fly Certificate?
A fit to fly certificate is a medical letter issued by a GMC-registered doctor confirming that a passenger is medically suitable to travel by air. It is not a standard document carried by all travellers — it is required only when a passenger has a medical condition that could be affected by air travel, or when an airline’s own policy requires one.
Airlines have a duty of care to all passengers and crew. When a medical condition creates a potential risk in the cabin environment — due to reduced air pressure, limited medical facilities, or the physical demands of travel — airlines may request a certificate before allowing boarding.
A fit to fly certificate typically confirms:
When Do Airlines Require a Fit to Fly Certificate?
Each airline sets its own medical policy, but the following conditions consistently trigger a fit to fly requirement across major UK and international carriers. If any of these apply to you, contact your airline before travelling.
Pregnancy
Most airlines require a fit to fly certificate from 28 weeks. From 36 weeks (32 for multiple pregnancies), many airlines will not carry passengers at all. Requirements vary — always check your specific carrier’s policy.
Recent surgery or hospitalisation
Flying too soon after surgery carries risks including blood clots and pressure-related complications. Airlines typically require a fit to fly letter confirming the procedure date, recovery status, and that air travel is medically appropriate.
Respiratory conditions
Conditions such as COPD, severe asthma, or reduced lung capacity may be affected by cabin pressure. Airlines may require confirmation of current oxygen saturation, medication needs, and whether supplemental oxygen is required during the flight.
Cardiovascular conditions
Recent heart attack, unstable angina, uncontrolled arrhythmia, or stroke within the preceding weeks typically trigger a fit to fly requirement. The certificate should confirm current cardiac status and that the patient is stable for travel.
DVT and blood clot risk
A recent DVT or pulmonary embolism, or high risk of thrombosis, often requires a certificate confirming treatment status, anticoagulation, and that travel is medically appropriate for the duration of the flight.
Infectious conditions
Communicable diseases including active tuberculosis, chickenpox, or other conditions that may pose a risk to other passengers typically require clearance before flying. An airline may request confirmation that the condition is no longer infectious.
Standard Letter or Completed Airline Form — Which Do You Need?
This is one of the most common points of confusion. Some airlines accept a standard doctor’s letter on headed paper. Others require their own MEDIF (Medical Information Form) or FREMEC form to be completed. Getting this wrong can result in the document being rejected at check-in.
Accepted by most airlines for straightforward cases such as pregnancy, recent illness, or minor conditions. The letter must be on professional headed paper, signed by a GMC-registered doctor, and include:
Required by some airlines for more complex medical situations — particularly where special assistance, medical equipment, or supplemental oxygen is needed on board. In these cases:
If you are unsure which format your airline requires, contact their special assistance or medical clearance team directly before booking a doctor’s appointment. MedicalCert doctors can complete both standard fit to fly certificates and specific airline forms where provided.
When You Do Not Need a Fit to Fly Certificate
Most passengers — including those with well-managed chronic conditions — do not need a fit to fly certificate. A certificate is not required simply because you take regular medication, have a disability, or have had a medical condition in the past.
You are unlikely to need a fit to fly certificate if:
When in doubt, check your airline’s own medical policy or speak to your GP. Not all conditions listed above are exempt in every case.
Clinical Review & Eligibility
Fit to fly certificates issued through MedicalCert are reviewed individually by GMC-registered UK doctors. Every application is assessed on its own clinical merits — certificates are not automatically generated.
Limitations & When In-Person Assessment Is Required
A fit to fly certificate does not guarantee boarding. Final acceptance is always at the airline’s discretion. The following situations require in-person or specialist assessment:
Final acceptance of any fit to fly certificate is determined by the airline. MedicalCert cannot guarantee boarding approval. This service operates within UK jurisdiction and in accordance with UK clinical standards.
Frequently Asked Questions
Need a Fit to Fly Certificate from a UK Doctor?
MedicalCert’s GMC-registered doctors can review your case and issue a fit to fly certificate where clinically appropriate — no GP appointment needed. Airline-specific forms can also be completed where provided.
Get a Fit to Fly Certificate →
Subject to clinical review. Final acceptance is always at the airline’s discretion.