As summer holiday season approaches, travellers everywhere are busy plotting itineraries, hunting for flight deals and perfecting the art of carry-on packing. But while most attention is given to the destination itself, travel experts say one of the most overlooked parts of any trip happens long before you check-in at the hotel: the flight.

Long-haul journeys may mean back-to-back rom-coms, complimentary drinks and surprisingly decent plane food, but spending hours in the air can also take a toll on the body. Extended periods of sitting, dry cabin air, jet lag and disrupted sleep often leave passengers feeling sluggish before their holiday has even begun. NHS research says that anyone travelling for more than four hours may face an increased risk of blood clots, while the Civil Aviation Authority (CAA) notes that low cabin humidity can contribute to dry eyes, lips and skin.

“A long flight feels much harder than it needs to when passengers treat the journey itself as an afterthought,” says Sarah Rodrigues, travel expert working with Avanti Travel Insurance.

With this in mind, she has shared her top six mistakes' holidaymakers commonly make on long-haul flights and the simple ways to avoid them:

1. Choosing the wrong seat

Many passengers choose a seat based on price, the view or whether they want to sit near family. But on a long-haul flight, comfort and accessibility can matter far more.

An aisle seat makes it easier to stand, stretch and move around the cabin without disturbing other passengers, which experts say is important on longer journeys. Regular movement can help ease stiffness and support circulation during flights lasting several hours.

“The best seat is not always the one with the window view,” says Sarah. “In order to stretch, move around and get up regularly, an aisle seat makes the journey much easier to manage.”

However, for travellers with pre-existing medical conditions, Dr Asimah, a medical expert working with Staysure, advises seeking clinical advice before flying long haul. “For those with a history of blood clots, reduced mobility or other health conditions, it is always a good idea to consult a medical professional to understand the best ways to keep yourself comfortable.”

Small adjustments can also make a big difference. “Compression socks apply gentle pressure to the legs, helping blood flow back towards the heart more efficiently during long periods of sitting. This can reduce swelling in the feet and ankles and may lower the risk of discomfort and some circulation-related issues on long-haul flights
Movement is one of the simplest ways to support circulation during a long flight. Even simple seated exercises, such as flexing your ankles or tightening your leg muscles, can help keep the blood flowing,” she adds.

2. Wearing uncomfortable clothes

Everyone loves a good airport outfit, but tight trousers and stiff shoes that feel fine at take-off can quickly become uncomfortable several hours into a flight.

Sarah says loose layers, breathable fabrics and comfortable footwear are usually the better option for long-haul travel. Cabin temperatures can vary during the journey, while sitting for long periods may also cause some passengers’ feet to swell slightly.

“Flight-goers may prioritise style at the airport, but comfort makes a much bigger difference on a long flight. Soft layers and shoes you can easily remove and put back on make the journey feel far less draining,” she says.

3. Ordering incorrect drinks

It feels tiresome to keep an eye on your drinks while on vacation but for some, the wrong drink can mean an uncomfortably long journey. Sometimes, travellers avoid water, so they do not have to keep getting up, while others rely on coffee, fizzy drinks or alcohol to get through the journey.

That can make long-haul flights feel even more draining. Dry cabin air can leave passengers feeling dehydrated, while too much caffeine or alcohol may make sleep disruption and jet lag symptoms worse.
“Alcohol might make you feel drowsy at first, but the aim is not just to sleep on the plane,” says Sarah. “It is to arrive feeling as steady as possible, especially if you want to make the most of the first day of your trip.”

Dr Asimah adds: “Cabin air is very dry, which can leave passengers with a dry mouth, dry eyes or a stronger feeling of thirst. While it is fine to enjoy a drink or two, too much caffeine or alcohol can contribute to dehydration and disrupt sleep, potentially worsening jet lag and leaving travellers feeling more tired when they land.”

4. Guessing medication timings across time zones

For Brits who take regular medication, long-haul flights can create confusion around when doses should be taken. Crossing multiple time zones may affect medication schedules, and guessing is not always safe.

To help manage this, it can be useful to note down the times you take your medicines in the UK and factor in the time difference, so you have a clear plan for when doses should be taken while abroad. This is especially important for travellers with pre-existing medical conditions, particularly those taking medication that needs to be taken at regular intervals or at specific times each day.

“Medication timing should be planned before travel, rather than worked out halfway through the journey,” says Dr Asimah. “For time-sensitive medication, keeping your watch on UK/home time can work, but when crossing multiple time zones it may be helpful to gradually adjust to local time while making sure you do not exceed your prescribed daily dose.”

She adds: “Always take medicines exactly as directed, with food or on an empty stomach where required, and seek advice from your doctor or pharmacist if you are unsure, particularly for long-term treatments.”

5. Packing essentials in checked luggage

Another common mistake is placing important items such as medication, glasses, chargers, or insurance documents in checked baggage.

For instance, if a portable power bank is discovered in a checked suitcase, it may be pulled for additional screening, delayed or even removed from the flight. In some cases, if the bag has already entered the baggage system, it may not travel until the issue is resolved.

Sarah says: “Your hand luggage should be your holdall for stress-free flying. Medication, insurance documents, chargers, a refillable water bottle and anything you genuinely rely on should stay with you, not in the hold.”

“Travellers are also advised to check airline and airport rules before flying, particularly when carrying these items to avoid unnecessary confusion and delays. If luggage is delayed, damaged or inaccessible during the flight, you could be left without the items you rely on most,” she adds.

6. Shying away from asking for an upgrade

It can feel awkward to ask, but Sarah says it is sometimes worth a try. “If the flight is empty and you are celebrating an anniversary or birthday, there is a chance you might get a business class upgrade.”
And if you are willing to splash a bit extra, it pays to be quick. Check in as soon as it opens, usually 24 hours before departure on the airline app, and you will see what seats and upgrades are still available. Sometimes upgrade prices can drop on the day of travel.

Most long-haul travel mistakes are not dramatic, but small things people often overlook. “These seemingly minor choices can have a big impact on how the first day of a holiday feels, which is why careful preparation is so important. Planning ahead shouldn’t just focus on the holiday itself, but also on the journey there.

Holidaymakers can also benefit from having travel insurance in place, helping to protect against unexpected delays, cancellations, or disruptions — and offering peace of mind from the moment they step onto the flight,” adds Sarah.