Are you a good airline companion? Or is the person next to you silently begging for escape?
People, if you are going on a plane, you need to wear deodorant.
I don't care what you do the rest of the year, but I do not want to be subjected to your body odour when we're squashed into a confined space with limited air flow.
I recently sat next to a man who was polite, friendly and doing a wonderful job of looking after the small boy with him, but every time he lifted his arms I felt nauseous.
It was blessedly only a two-hour flight but by the time it was over, I felt like I needed a shower.
I'd been unable to relax and unable to concentrate on my book, so it was a long two hours and I was very glad we were not going to London.
It seems I'm not alone in having smelly folk as my least-favourite airline companions: a Harris Interactive poll in the United States found nearly two-thirds of passengers would rather sit next to a crying baby than an odorous adult.
And we all know how popular crying babies are on planes, as evidenced by airlines introducing child-free sections for travellers willing to pay a premium for some peace.
Equal first on my list of least-favourite fellow travellers are those who don't fit into their seat, leaving me with about half of mine.
However, I have a lot more sympathy with these passengers, as being overweight is a lot more complicated than buying a can of deodorant.
Next on my list are those who won't shut up, no matter how many subtle or not-so-subtle hints you drop.
A friend of mine travelling alone on a long-haul flight was regaled with tales of her fellow passenger's travels to Asia to find himself a wife ... I won't go into the sordid details.
Some people might enjoy the opportunity to chat to a stranger on a plane but for me it is a bit of time out or a chance to get some work done.
I have been known to wear headphones even when I'm not listening to anything, just to get some peace and quiet.
Call me fussy, but I'm not too keen on those who drink their way through flights, either.
I'm all for having a couple of drinks on a long journey but I don't feel the need to see how much I can pour in (nor do I want to be that person getting up to go to the loo every half an hour).
I once watched a woman sitting with her non-drinking husband order drinks for them both so she could double up, which was not a good look after eight hours.
The worst experience I've had on a plane was due to alcohol: a man sitting next to me on an international flight had a complete personality change after many drinks.
His behaviour became so intimidating that other passengers stepped in and the captain radioed ahead for police to board when we landed.
Then you get the seat slammers, who throw their seat into full– recline as soon as you take off and leave it that way until landing.
There's no generally-accepted rule on seat-reclining but I keep mine upright or close to upright on daytime flights or when meals are being served, only reclining it fully at night time.
I don't think you need to seek the permission of the person behind but you do need to recline gently rather than slamming your seat into someone's face.
When it comes to kids, I'm not overly bothered by crying babies or chatty children – I've had plenty of practice with that – but seat-kickers do my head in.
I would never allow my children to kick the seat in front and believe any child old enough to reach that far is old enough to be told no.
An etiquette issue raised by a reader is window blinds and whether they should be up or down at various points of the flight.
The reader told me he likes to keep the blinds up during the flight but has had battles with others who insist they should be down.
This is a tricky one, as different passengers have different needs on long flights – and it can be hard to see television screens with the blinds up – so I don't really have an answer to that one, other than making sure you have an eye mask if you want to sleep.
I am, however, pretty clear about the BO.
What are your rules of plane etiquette? Have you ever experienced bad behaviour from your neighbour on a flight? Post your comments below.