With one baby and a straightforward pregnancy, the RCOG says you can fly until 37 weeks. Airlines stop you earlier: of the eight carriers below, three carry you to the end of week 36, three to the end of week 35, and the strictest to 34. With twins, nearly all of them stop at 32. From week 28, most want a letter.
Two different answers, then. The medical one is about your body, and it is more generous than most women expect. The airline one is about an airline's preference for not meeting your baby at 38,000 feet. It is a commercial rule, every carrier has written its own, and the airline's date is the one you plan around.
Women ask us this question more than any other, usually with a wedding, a family visit, or one last trip somewhere warm behind it. So here is every rule in one place, checked against each carrier's own published terms, not against what a forum remembered.
Checked 27 August 2026. Airlines change these quietly, so confirm your own booking before you pay for anything.
| Airline | You can fly until (one baby) | Twins or more, until | Paperwork |
|---|---|---|---|
| easyJet | The end of your 35th week | The end of week 32 | None at any stage |
| Jet2 | The end of week 35 | The end of week 33 | Doctor's certificate after the end of week 27, dated within 7 days of flying out and 16 days of coming home |
| Ryanair | The end of week 36 | 32 weeks | Fit-to-fly letter from a doctor or midwife from week 28, dated within 2 weeks of departure, stamped (their form has a stamp box) |
| British Airways | The end of week 36 | 32 weeks | Their form or an official letter from a doctor or midwife, completed and stamped, from week 28, covering the whole trip |
| Wizz Air | 34 weeks | 32 weeks | Medical certificate from week 28, issued within 6 days of the flight |
| Vueling | The end of week 35: they stop you from week 36 | 32 weeks | Original letter, valid weeks 28–35, with your doctor's registration number and signature |
| TAP | 36 weeks, or 4 weeks before your due date, whichever comes first | 32 weeks | Medical statement from week 28 |
| KLM | No hard rule: they advise against flying from 36 weeks | No published twins rule; ask them | Nothing to file; they advise clearance from your own doctor |
The earliest hard stop is Wizz Air, at 34 weeks. And three things in that table catch people at the airport rather than at home, which is the worse place to find out.
"The end of your 35th week" can mean two different weeks. Read strictly, it means 34 weeks and 6 days. Read the way most of us would read it, it means 35 and 6. That is a full week of difference, and a bag drop is no place to argue grammar with an airline. If your dates sit near a cutoff, ask the airline to confirm your booking in writing. They will.
The limit applies to your flight home as well as your flight out. Jet2 dates the outbound and the return separately, and Ryanair's form asks how many weeks you will be on each leg. Count your weeks on the day you land back, not the day you leave.
The paperwork has its own deadline. Most airlines only accept a letter dated close to the flight, six days for Wizz Air and seven for Jet2, so a letter you sensibly organised early may need re-dating for the trip itself.
Or let the arithmetic do itself. Our free Flying-Window Planner takes your due date and sends you your window: your last day to fly, the day your airline starts asking for a letter, and which travel dates still work for you.
From week 28, most airlines want something in writing. It is a small thing to organise and an easy thing to leave too late. What has to be on it:
The stamp is the one that catches people. British Airways requires its form "completed and stamped"; Ryanair and Jet2 both print a stamp box. A perfectly good signed letter without one gets sent back at the desk.
Who signs it depends on the airline, and this is worth knowing before you book the appointment rather than after. British Airways and Ryanair accept your midwife. Jet2 asks for a doctor's certificate. Vueling wants a doctor, with their registration number on the page.
Ryanair, Jet2 and British Airways each publish their own form. Download it and take it to the appointment: every field they will check at the desk is already printed on it, which is easier than hoping a letter happens to cover them all.
Ask sooner than feels necessary. The NHS says you may have to pay for the letter and wait several weeks, and practices set their own fee. Then time the document to the flight, since most airlines only accept one dated within a week or two of travel.
⚠️ We are quoting the RCOG here. Your midwife or doctor comes first.
The RCOG lists circumstances in which you may be advised not to fly at any stage: an increased risk of going into labour early, severe anaemia, sickle cell disease with a recent crisis, recent significant vaginal bleeding, or a serious heart or lung condition that makes breathing difficult.
If any of those apply, or if your pregnancy has needed extra attention of any kind, then the table above is not the thing to follow: the people to follow are your midwife and your doctor. None of this page is a substitute for their advice about your pregnancy.
Almost every carrier draws the twins line at 32 weeks, and the RCOG's clinical window agrees: before 32 for an uncomplicated multiple pregnancy. Jet2 runs to the end of week 33. If you are carrying twins and want a third-trimester trip, book it for the early side of the window and give yourself room. A twin pregnancy has enough moving parts without an airline's calendar joining them.
Yes, with every airline in the table, but this is the week the paperwork starts. From 28 weeks most carriers want a fit-to-fly letter or their own form, so this is the week to book the appointment.
Yes, on every airline listed, with the letter. This is also about the last comfortable moment to plan something that needs a return flight a few weeks later.
With one baby, yes, on every airline here. With twins, 32 weeks is where nearly every carrier stops, and a few word it as "the end of week 32", which puts you exactly on the boundary. Treat the door as closed and travel earlier.
Only with one baby, and only on the carriers that run latest: Ryanair and British Airways to the end of week 36, and TAP to 36 weeks unless that falls within four weeks of your due date. Check your airline's exact wording, and remember the flight home counts.
Staff can ask at check-in or at the gate, and from 28 weeks the burden is on you to show the paperwork. Whether anyone asks on the day is luck. The price of losing that bet is your boarding, which is why we would not take it.
The wording matters more than the brand. Check two things in the policy document itself: whether cancellation is covered if a doctor advises against travel before you go, and whether that cover extends to the trip cost rather than only the flights. On many policies it does not.
mom'z runs five-day pregnancy retreats near Barcelona, near Lisbon and in Somerset, ten to fifteen women at a time, each attending on her own, in what our guests tend to call a solo babymoon. Every woman who comes to one has to get there first. So we read airline conditions for a living, and we keep this table checked.
If you are working out whether a trip still fits your pregnancy, the Flying-Window Planner will send you your dates in a minute. And if what you are quietly looking for is a reason to go somewhere calm before the baby comes, the dates are here.
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