Fit To Fly Certificates For Chronic Illnesses
Having a chronic illness does not automatically prevent you from flying, but it does mean the fit-to-fly assessment requires more care and specificity. The key question is not whether your condition exists, but whether it is currently stable, adequately managed, and compatible with the physiological changes that air travel creates. For most people with well-controlled chronic conditions, flying is possible with the right documentation and preparation.
This guide explains how common chronic conditions affect fit-to-fly assessment, what makes a chronic illness a contraindication versus a managed condition, and what your certificate needs to say to satisfy airlines and travel insurers.
This page is informational and does not replace clinical assessment. Airline policies vary. The UK Civil Aviation Authority states that the final decision whether or not to carry a passenger is that of the airline, so no certificate, from any provider, can guarantee that you will be allowed to board.
How Common Chronic Conditions Affect Fit-to-Fly Assessment
Each chronic condition carries its own risk profile at altitude. Cabin pressurisation, reduced oxygen partial pressure, and long periods of immobility all affect chronic conditions differently. The table below follows the UK Civil Aviation Authority’s guidance for health professionals. It is a guide to how a clinician assesses the question, not a set of rules that decides it, and where the CAA publishes no condition-specific guidance that is said plainly.
| Condition | When flying is generally safe | When flying may not be safe |
|---|---|---|
| Stable coronary artery disease / angina | CAA guidance is that stable angina pectoris is usually not a problem in flight, and that after an uncomplicated myocardial infarction a patient may travel after 7 to 10 days if there are no complications | The CAA lists unstable angina and decompensated congestive heart failure as contraindications to commercial flight, along with a complicated myocardial infarction within 4 to 6 weeks |
| COPD / chronic respiratory disease | The CAA describes the most practical test as whether the patient can walk 50 yards or metres at a normal pace, or climb one flight of stairs, without severe dyspnoea. If so, they are likely to tolerate the normal aircraft environment | Severe breathlessness on minimal exertion, or an active or contagious chest infection, where the CAA advises deferring travel until the infection is controlled. An untreated pneumothorax is an absolute contraindication. A hypoxic challenge giving a PaO2 below 55 mmHg indicates a need for medical oxygen rather than a bar to flying |
| Diabetes (Type 1 or 2) | CAA guidance is that air travel should not pose significant problems for patients with well-controlled diabetes, provided adequate medication and monitoring equipment are carried in hand baggage | Poorly controlled diabetes with frequent hypoglycaemia. The CAA notes that insulin pump users should be aware that cabin pressure changes can affect delivery, and that doses may need adjusting where a journey gains or loses more than two hours |
| Epilepsy | Well-controlled epilepsy, compliant with medication, with emergency medication carried in hand baggage | The CAA states that any passenger with uncontrolled epilepsy, or any new onset of seizures, will require medical clearance before flight, and that a passenger should wait at least 24 hours after a seizure before flying |
| Inflammatory bowel disease (Crohn’s / UC) | In remission or stable on medication with no active severe flare. Note that the CAA publishes no passenger guidance specific to inflammatory bowel disease, so this rests on the treating clinician | An active severe flare, or recent surgery. CAA guidance is that travel should be avoided for 10 days following abdominal surgery, and for around 24 hours after a laparoscopic procedure because of residual CO2 gas. Intestinal gas expands by roughly 30% by volume at a cabin altitude of 8,000 feet |
| Severe anaemia (chronic) | CAA guidance is that patients with a haemoglobin greater than 8 g/dL may travel without problems, assuming there is no coexisting condition such as cardiovascular or respiratory disease. Chronic anaemia is usually tolerated at a lower level than anaemia of acute onset | Below 7.5 g/dL the CAA advises that a special assessment should be made and supplemental oxygen considered. Sickle cell trait is not a particular problem at normal cruising altitude, but the CAA advises that patients with sickle cell anaemia should travel with supplemental oxygen and defer travel for approximately 10 days after a sickling crisis |
| HIV | Well-controlled on antiretroviral therapy, clinically stable, with no active infection. The CAA publishes no HIV-specific passenger guidance, so the assessment turns on current stability and any coexisting condition | An active opportunistic infection, which is treated like any other active infection, or significant coexisting respiratory or cardiac disease that would limit tolerance of the cabin environment |
Source: UK Civil Aviation Authority, guidance for health professionals on assessing fitness to fly. Meeting any of these descriptions does not by itself clear you to travel, and failing one does not by itself ground you. The airline decides.
What a Chronic Illness Fit-to-Fly Certificate Must Include
A standard fit-to-fly certificate for a passenger with a chronic illness needs more content than one for an otherwise healthy person. The certificate should specifically address:
Certificate contents for chronic conditions
- The nature of the chronic condition
- Current treatment and how well controlled it is
- Most recent relevant clinical parameters, for example HbA1c for diabetics, FEV1 for COPD, viral load for HIV
- Any special requirements during the flight such as supplemental oxygen, access to medication, or seating requirements
- Confirmation that the condition is stable and the passenger is fit to fly on the specified dates
- Any relevant precautions the airline or crew should be aware of
How airline medical clearance actually works
A certificate is evidence, not permission. The CAA notes that most airlines have medical advisors who clear passengers as fit to fly, and that clearance can be given by telephone or through a MEDIF form, which structures the medical information in a way most airlines can process. The key information they want is the nature and severity of the condition, how stable it is, what medication is being taken, and anything relevant about mobility. Send it well in advance of the flight, because the CAA is explicit that the final decision whether or not to carry a passenger is the airline’s.
Supplemental oxygen during flights
Therapeutic oxygen has to be arranged with the airline in advance. CAA guidance is that where supplementary oxygen is required the airline should be notified well in advance using a MEDIF form, so that the service can be provided, and that some carriers make a charge for it. Airlines commonly offer fixed flow rates of 2 or 4 litres per minute, so your doctor’s certificate should specify the rate you need. Individual airlines set their own notice periods and their own approved list of portable oxygen concentrator models, so check the medical clearance page of the carrier you are booked with.
Fit-to-Fly Certificate for Chronic Conditions, Same Day
GMC-registered doctors assess your fitness to fly with a chronic condition and issue a certificate setting out the clinical detail airlines ask for. Online, same day, full refund if we cannot issue. The final decision on carriage always rests with the airline.
Frequently Asked Questions
Do I have to declare a chronic condition to my airline?
There is no general legal duty to tell an airline about a health condition, but the CAA is clear that you must contact the airline before your flight if you will need help at the airport, wish to carry additional medical equipment, or will need extra oxygen during the flight. The airline may then ask your doctor to complete a MEDIF form before it confirms whether you are fit to fly. Travel insurance is a separate matter, insurers typically require disclosure of pre-existing conditions when you buy the policy, and non-disclosure can invalidate a claim.
How often do I need a new fit-to-fly certificate for a chronic condition?
There is no universal rule, and the CAA does not set one. Individual airlines decide how recent a certificate has to be, and the windows vary, so check the medical clearance page of the carrier you are booked with before you assume an older letter will do. For a stable chronic condition, expect to need a certificate for each trip rather than one document that covers you indefinitely, and expect the airline to want any MEDIF form completed close to the date of travel.
Can I get travel insurance with a chronic illness?
Yes. Specialist travel insurance for people with pre-existing medical conditions is widely available, though it usually costs more than a standard policy. You must declare all relevant conditions and treatment accurately when you buy it. If a mainstream insurer will not cover your condition, ask to be signposted to a specialist provider rather than going without. Buying a policy without declaring a chronic condition is a serious risk, because a medical emergency abroad involving that condition would not be covered.
What if my condition worsens between getting the certificate and flying?
If your condition significantly deteriorates after a certificate is issued, the certificate may no longer accurately reflect your fitness to fly. You should seek a new assessment if there is any material change, particularly for cardiac or respiratory conditions where an acute event between the certificate date and travel could make the existing certificate clinically inaccurate. Notifying your insurer of a change in health status before travel is also advisable, because an undeclared deterioration can affect cover.
I need supplemental oxygen during the flight. How do I arrange this?
Contact your airline’s special assistance or medical desk as early as you can. CAA guidance is that the airline should be notified well in advance using a MEDIF form so the service can be provided, and that some carriers charge for it. You will need a doctor’s certificate specifying the required flow rate and confirming clinical necessity, and airlines commonly offer fixed rates of 2 or 4 litres per minute. If you use a portable oxygen concentrator, contact the airline to confirm your device model is on its approved list, because approval and the required notice period vary by carrier.
Fit-to-Fly with a Chronic Illness, Online Assessment
GMC-registered doctors carry out detailed flying fitness assessments for passengers with chronic conditions and issue certificates covering the clinical detail airlines commonly ask for. Acceptance remains a decision for the airline.
