Not Fit to Fly Certificate - Unable to Fly Medical Letter
An unable to fly due to medical reasons letter is an official document from a GMC-registered doctor confirming you cannot travel by air due to illness, injury, or a medical condition.
Airlines, travel insurers, and holiday providers require a not fit to fly certificate when processing cancellation claims or issuing refunds, a standard GP letter is rarely sufficient.
✔ Accepted by airlines, travel insurers and holiday providers.
✔ Covers illness, injury, post-surgery and pregnancy complications.
✔ Most same day. All by 9AM next morning. From £39
✔ Full refund if the GP cannot issue.
Get my certificate 
Receive a full refund if we can’t provide a certificate
How It Works
Complete a short online questionnaire
No appointment required. Complete a short medical questionnaire and upload any supporting evidence.
Doctor reviews your evidence
A GMC-registered doctor reviews your submission individually. No automated approvals.
✔ Full refund if the GP cannot issue.
Receive your certificate
Certificates arrive most same day, all by 9AM next morning, delivered as a signed PDF direct to your inbox.
What our patients say
Verified reviews from real MedicalCert patients
Anne S.
July 2025
Certificate by 9am — we made our flight
This company did exactly what they said they would. They got us our medical certificate by 9am the next day. Without them we wouldn't have been able to fly to Australia.
Mrs B.
July 2025
Super fast — and cheaper than my GP
The service was super fast and I received the certificate within 24 hours. I paid for the express service and it still cost less than my GP would have charged. Highly recommend.
Laura R.
June 2025
Quick and exactly what I needed
Quick service. Got what I needed. The process was smooth and straightforward, and I received everything I required without any hassle.
Unable to Fly Due to Medical Reasons Letter
An unable to fly due to medical reasons letter — also called a not fit to fly certificate or unfit to travel certificate — is a doctor-signed document confirming that a patient was medically unable to travel by air at the time of assessment. It is most commonly required by airlines, travel insurers, and holiday providers to support refund or rebooking requests following a cancellation on health grounds.
A MedicalCert unable to fly letter is signed by a GMC-registered UK doctor, includes a QR verification code, and is issued the same day — providing the documentation your airline or insurer requires to process your claim.
Fit to Fly vs Not Fit to Fly — Which Do You Need?
These two documents serve opposite purposes. Choosing the wrong one will delay your claim.
✈ Fit to Fly Certificate
- →Confirms you ARE medically safe to travel
- →Presented at check-in to allow boarding
- →Used for pregnancy, post-surgery, stable conditions
🚫 Not Fit to Fly Letter
- →Confirms you were UNABLE to travel for medical reasons
- →Submitted to airline or insurer after missing a flight
- →Used to support refund, rebooking, or insurance claim
If you have already missed your flight or holiday due to illness, this is the document you need. If you need clearance to board a flight despite a medical condition, see our fit to fly certificate.
When Is an Unable to Fly Letter Used?
Airline refund or rebooking
Airlines distinguish voluntary cancellations from medically necessary ones. A doctor’s letter may support a request to waive change fees or obtain a partial refund — subject to each airline’s medical cancellation policy.
Travel insurance claim
Most travel insurance policies require medical evidence before processing a cancellation claim. The insurer requires a letter dated close to the flight date, confirming the condition and that travel was clinically inadvisable.
Package holiday provider
Holiday providers and travel agents typically require the same documentation as insurers to release a rebooking or credit. A letter issued promptly is more effective than one obtained retrospectively.
Cruise cancellation
Cruise operators follow similar requirements to airlines. A certificate that covers sea travel as well as air travel is useful where the booking involves a cruise. See also our travel cancellation certificate.
Visa or travel obligation
If a medical condition prevented attendance at a scheduled visa appointment or mandatory international commitment, a doctor’s letter confirms the legitimate reason for non-attendance.
Work or academic travel
Employers or educational institutions may require documentation if illness disrupted a required business trip, conference, or international study placement.
Medical Conditions Commonly Covered
A not fit to fly letter can be issued across a wide range of clinical scenarios, subject to individual review. Common examples include:
Each case is assessed on its clinical merits. The letter will not contain exaggerated claims — it reflects an honest assessment of the information and evidence provided.
Important: Refunds Are Not Guaranteed
Understand what this letter does and does not do
A not fit to fly letter supports your submission to an airline or insurer but does not guarantee a refund or claim outcome. Airlines are not legally required to refund non-refundable fares because a passenger was ill — though many have goodwill policies. Travel insurance claims are assessed against the specific policy wording and exclusions set by the insurer. Obtaining medical documentation promptly, as close to the original travel date as possible, significantly strengthens your submission.
What the Letter Includes
Letter contents
- ✔Your name, date of birth, and contact details
- ✔The medical condition or symptoms that prevented travel
- ✔Confirmation that travel was clinically inadvisable at the time
- ✔Dates of the period of medical unfitness to travel
- ✔GMC registration number of the signing doctor
- ✔Unique QR code for verification by airline or insurer
How to Get Your Unable to Fly Letter
Complete the online consultation form
Describe your illness or injury, the dates you were unable to travel, and your booking details. Upload supporting evidence — photos of symptoms, discharge letters, prescriptions, or test results.
GMC-registered doctor reviews your case
Your submission is reviewed the same day. If additional information is needed, the doctor may contact you before issuing.
Letter delivered to your inbox
If clinically appropriate, your signed PDF letter arrives same day (submit before 9pm) or by 9am next morning. If the doctor cannot issue, you receive a full refund.
Submit to your airline or insurer
Submit the letter alongside your booking confirmation and any insurer claim form. Keep a copy for your records.
Unable to Fly Letter FAQs
Clinically Reviewed By
Dr Maria Knobel
Medical Director, Nobel Medical LLC
GMC Registration
► 7495073 – View on GMC register