On a flight from London to Barcelona, my first awareness of an incoming cold came as the plane began its descent: a pain above and below my eyes so intense I thought some essential component within me might genuinely burst. It didn’t, but by nighttime the sinus pressure had developed into the full-on cold it heralded.

I had no warning that time, but usually you feel it coming. The first signs turn up a day or two before the flight, and the question becomes: will this get bad enough that I shouldn’t fly? The official advice is quite clear: stay home until you’re better, which is sound, but we can admit very few people follow it. Those first days are also the hardest to judge, since nobody can say how bad a cold will get, and your sinuses can turn on you without warning, as I found out. So here is a more pragmatic answer: a cold that’s already on its way out is usually fine to fly with, provided you know how to look after your ears during the descent before landing.

When you’re probably fine

You’re probably fine if the cold is confined to your nose and throat, you feel a little better than you did yesterday, and you’ve gone 24 hours without a fever and without fever-reducing medicine. That’s the CDC’s yardstick for getting back to normal life. It isn’t written with flights in mind, but it’s the nearest thing to an official green light.

There’s a quick check you can do at home, too. Pinch your nose, close your mouth and blow out very gently. If your ears pop, that’s encouraging, and if they won’t clear on the ground, they’re unlikely to manage in the air, which is where I’d start looking at rebooking.

When to stay home

If you have a fever, or you feel properly ill or badly congested rather than merely stuffed up, stay home. A tickle in the throat that may come to nothing is harder to call, and most of us wouldn’t cancel a flight over one. The official line is stricter, though: the CDC says people with a respiratory infection should delay travel until they’re no longer contagious, and the FAA goes further, saying it may be advisable not to fly at all if you suspect you have a cold. If you do go, the pinch test above is the check I’d trust on the morning of the flight. If you’ve had an ear or sinus infection recently, or have any other medical concern, talk to your doctor first.

If you do rebook, ask the airline what it can do for an unwell traveler and check whether your travel insurance covers illness.

What your ears are dealing with

Ear trouble is rare as the plane climbs and mostly takes effect during the descent. A small tube links the middle ear to the back of your nose and opens each time you swallow or yawn, and a cold swells it shut, so the pressure builds against the eardrum. In your ears, it feels like a dull ache and muffled hearing, a bit like having cotton stuffed in them, and most cases are mild, though don’t dismiss it: MedlinePlus lists an ear infection or a ruptured eardrum as possible complications (thankfully quite rare). If you’re anything like me, the same swelling can block your sinuses too, usually as the plane comes down and with little or no warning.

How to get through the descent

The trick is to start as soon as the plane begins to come down. Stay awake, since you swallow far less when you’re asleep (set an alarm if you tend to nod off), and keep swallowing with gum or a candy, yawning whenever you can. If your ears still feel blocked, try the pinch-and-blow from earlier before it starts to hurt, but keep it gentle, because the FAA warns that blowing hard with a cold can push infected material into the tube. If it doesn’t work the first time, try again, and stop if it hurts.

If your ears haven’t settled a few hours after landing, or you have a fever, severe pain, or any drainage or bleeding from the ear, see a doctor. Talk to your pediatrician before flying with a young child who has a cold, since children can’t be asked to clear their ears on demand.

The person in the next seat

Then there’s everyone else. Cabin air is refreshed 20 to 30 times an hour and passes through HEPA filters, which is reassuring until you remember the person next to you (or two people, if you’re in the middle).

Many of us think of a mask as something you wear to protect yourself, but traveling through Japan showed me that people who aren’t well often wear one for the benefit of everyone else. I’d do the same on a flight, with a well-fitting mask and every cough covered. That applies even once you’ve passed the 24-hour mark, since the CDC suggests taking extra precautions around other people for the next five days.

Frankly, none of this does much to magnify the glamour of flying, but it does work. You may still land with a head that feels as if it belongs to someone else, though at least you’ll see it coming, which is more than I did over Barcelona.

Sources

CDC Yellow Book, “Air Travel”

https://cdc.gov/yellow-book/hcp/travel-air-sea/air-travel.html 

FAA, “Trapped Gas”

https://www.faa.gov/pilots/training/airman_education/topics_of_interest/trapped_gas 

MedlinePlus, “Ear barotrauma”

https://medlineplus.gov/ency/article/001064.htm 

CDC, “Precautions When Sick”

https://www.cdc.gov/respiratory-viruses/prevention/precautions-when-sick.html