The airline's email is short and polite: before you travel, please provide a letter from a doctor. The booking was made months ago, before the operation or before the pregnancy reached this stage, and now there is a date, a form of words nobody quite understands and a feeling that the whole trip rests on one sheet of paper. Most people who ring about this feel reasonably well. What worries them is being turned away at the gate.
So the plain question is this. Do you actually need a fit to fly letter, what does a doctor have to check before writing one, and what happens if the honest answer is not yet? It helps to be clear from the start that a letter records an assessment. The airline still makes its own decision.
Chest pain, signs of a stroke, severe breathlessness, heavy bleeding, a severe allergic reaction or symptoms of sepsis need 999 or A&E immediately. For urgent advice that cannot wait, call NHS 111.
What does a doctor check before writing a fit to fly letter?
The first thing I look at is not you. It is the airline's own wording. Carriers set their own rules, and they differ on what they want confirmed, how recently the letter must be dated and whether they insist on a form of their own. Bring the email, the form or a printout of the airline's medical page, because I cannot write to a requirement I have not read. A letter that answers the wrong question is how people end up back at the check in desk with a problem.
Then the flight itself. How long it is, when it leaves and when you come back. A short hop and a long haul flight ask different things of the body, and a return trip means the assessment has to make sense for the flight home as well as the flight out.
After that comes the reason the airline asked. Most requests fall into a few groups, and each has its own questions.
After an illness or an operation
I want dates: when the operation was, when you left hospital and what the discharge summary says. Cabin pressure is lower than at ground level, so anything that affects breathing matters, and so does air that can remain in the body after some kinds of surgery. I listen to the chest, check oxygen levels and pulse, look at the wound if there is one, and ask about pain or swelling in either calf, because a clot after surgery is a quiet risk that a long flight adds to. If the surgical team gave you advice about when you could fly, that advice comes first, and I will not write against it.
In pregnancy
For a pregnancy fit to fly note, the questions are about the pregnancy as much as the flight. How many weeks you will be on the outbound and return dates, whether you are expecting one baby or more, and whether there have been complications such as bleeding or raised blood pressure. Bring your maternity notes, because the dates and scan findings need to come from the record rather than from memory. The note confirms your stage of pregnancy and what the assessment found. It does not replace the advice of your midwife or obstetric team, and if they have advised you not to fly, I will not write otherwise.
After chickenpox
Here the airline wants to know that you are no longer infectious. In practice that means looking at the spots, all of them, to see whether every one has crusted over. A new crop appearing changes the answer. Because the question is about how things look on the day, it makes sense to book the assessment close to the flight rather than a week ahead.
The second layer is worth asking about, as it so often is. When this comes up in consultation, a request for a letter sometimes sits on top of something else: a fear of flying that has quietly grown over the years, or a recovery that is slower than anyone has admitted out loud. Those conversations belong in the appointment too.
If the examination supports it, the letter is written. If it does not, I say so, explain why and talk through what would need to change before you travel. Letters and certificates are provided where clinically appropriate after assessment, never as a formality, and the wording reflects what was actually found.
When should you be seen sooner, or not fly at all?
Some symptoms mean the question is no longer about a letter. Get help first if you notice any of these:
- Chest pain, breathlessness at rest or coughing up blood. Call 999.
- A painful, swollen calf after an operation or a long period of sitting still. Contact NHS 111 that day.
- Bleeding, leaking fluid, regular tightenings or a change in your baby's movements in pregnancy. Contact your maternity unit now.
- A fever, feeling steadily more unwell or new spots appearing in the days before you travel.
- A wound that becomes red, hot or starts to leak after surgery.
None of these is a reason to panic. They are a reason to put the letter to one side and be assessed properly first.
What should you bring to the appointment?
The airline's wording or form. Your flight dates, both ways. Any discharge summary or operation note. Your maternity notes if you are pregnant. A list of your current medicines. If you are also travelling with medicines that may need explaining at a border, mention it when you book, because a travel letter is a separate document with a separate purpose. If the trip needs vaccines as well, our travel vaccinations page is the place to start.
How does a fit to fly assessment work at Clinique Alpa?
The assessment is face to face at 466 Green Lanes, Palmers Green, because most of these letters depend on an examination. You see a named doctor, and there is time to go through the paperwork properly rather than at speed. The clinic is open Monday to Friday 09:00 to 20:00 and Sunday 09:30 to 17:30, and is closed on Saturday.
The pregnancy fit to fly note is £250 and includes a 30 minute assessment. The chickenpox recovery certificate is £180. For a letter after an illness or an operation, call before you book and tell us what the airline has asked for, so we can tell you which appointment fits and what it costs. If you are flying because you are moving overseas for good, I have written about a health check before you go as well.
Written by Dr Mitesh Parmar, MBBS MRCGP, Principal GP and Clinical Director at Clinique Alpa, 466 Green Lanes, Palmers Green, London N13 5PA. This article is general information, not personal medical advice. In an emergency call 999. For NHS advice call 111 or visit nhs.uk.