Are you flying somewhere soon? You might not realise it but there is one thing you shouldn't do when you're on a plane even if it seems harmless.

You might think that as long as you’re comfortable, sleeping on a plane is a good idea but that's not always the case.

A sleep posture expert has shared one thing you should never do when sleeping on a plane and it might surprise you.

James Leinhardt has taken to TikTok to share three tips to help people sleep comfortably on a plane.

@levitex Comfy in economy? It’s not impossible🫡 #plane #sleeping #sleepingonplanes ♬ original sound - Levitex

His video on the social media platform has amassed 3.7 million views and 89.8k likes, at the time of writing.

One thing you should never do when sleeping on a plane

While there are a few different ways you might be able to fall asleep on a plane, James advises that you never lean forward and sleep with your head on the table in front of you.

Here are some tips from James to help you sleep comfortably on a plane.

James says: “How difficult is it to sleep comfortably on a plane? It's nearly impossible, particularly on long haul.”

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In the TikTok video, James goes on to provide three tips for sleeping on a plane.

"Make sure you recline your chair," James begins.

"Because you will distribute your body more evenly and there's less peak pressure coming down on your bottom."

He also shares advice on how to support your neck: "You need to support your neck, and not with those squishy memory foam nonsense things that will let you collapse.

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"If you just get your old jumper, stick it round your neck, and use an old elastic band or a hair bobble and support that neck.

"When you do that your head is not going to drop and flop as much and you get that support."

James explains: "Like in sleep we try to bring the bed to the person, the same is true in the chair. We always have this big hole between our back and the chair.

"Stick a lumbar roll or a cushion (in there) and you're much better supported and you can get a half-decent sleep."