A recent British Airways survey asked travelers from five countries about unmannerly behavior on airplanes. (izusek/Getty Images)

Unless you are ensconced in first class, sleeping on a plane is as intimate as dozing off in a waiting room on jury duty — everyone on the aircraft knows the decibel level of your snoring and the sad state of your socks.

To gauge how passengers perceive and handle nightmare flight scenarios, British Airways surveyed 1,500 travelers from the United States, the United Kingdom, France, Germany and Italy. The responses are eye-opening, but do not necessarily represent the gold standard of politesse. For the best practices at high altitudes, we reached out to Lizzie Post, a president at the Emily Post Institute in Burlington, Vt., and co-host of the podcast “Awesome Etiquette.” Here are the insights from your fellow travelers — and the final word from the manners expert.

●When it comes to armrests, 67 percent of respondents said that passengers should commandeer only one side and leave the other for their neighbor. More than 40 percent of British and American passengers occupying the middle seat said they were most likely to monopolize both armrests. Travelers from Italy, France and Germany were more courteous: Nearly half said the valuable real estate should go to the first person who asks.

Lizzie says: "Don't try to stake a claim on the armrest. Share it." She recommends sharing the physical space (for instance, you take the front section and your seatmate claims the back portion) or take turns using it.

●Shoes off is okay (59 percent); sockless is not okay (87 percent). Not surprisingly, three-quarters of Italians, who come from the Land of Gucci Loafers and Salvatore Ferragamo Pumps, turn their noses up at passengers who remove their footwear.

Lizzie says: "Out of consideration for other passengers, to the best of your ability we advise you to keep your shoes on while on the airplane."

●If the person in the aisle seat is snoozing and you need to access the lavatory, do you wakey-wakey? Yes, according to 80 percent of surveyed subjects, but only once per trip, added 40 percent. A third said that they would steeplechase over the slumbering body, but were torn over the best approach. More than half agreed on a face-to-face (or derriere-to-tray table) exit strategy.

Lizzie says: "Absolutely wake the person up. When possible, the aisle person has an etiquette obligation to make it easy for the other people."

●Bedtime stories should stay brief, according to more than 80 percent of travelers. Seatmates should exchange a quick hello and a smile, then zip the lip. Americans (42 percent) disapprove of sharing personal tales and will slip on headphones to cancel the conversation. Brits use the skip-to-the-loo excuse. Italian and French travelers are more magnanimous: 80 percent of Italians consider small talk appropriate and half the French respondents consider flying a friendship-forging opportunity.

Lizzie says: "Brief chitchat is nice, but not obligatory. You can gauge if this is a good person to further the conversation with." To ease out of the situation, Lizzie suggests telling the person you are going to tuck into your book or listen to your music now and pop in your ear buds.

●On the topic of snoring, 66 percent said they won’t nudge a nose-bugling neighbor, but will mute the noise by cranking up the volume on their entertainment system. However, 20 percent of Brits will give the offender a shove and then feign innocence.

Lizzie says: "Ignore it and block it out with your own entertainment system. Wax earplugs are great."

●Sleeping accessories vary by nationality. Americans prefer noise-cancelling headphones; Italians and the French favor diva eye masks.

Lizzie says: "There is no etiquette offense, though other people might have to tap you harder if they need you to move."

● The majority of travelers say switching seats is acceptable, but only after checking with the flight attendant. Brits are the most likely to nab a new spot. They usually pounce after takeoff and once the pilot has turned off the seat-belt sign.

Lizzie says: "Asking the flight attendant is a good idea. It is respectful, and you're holding onto a ticket that says you are in a different seat, so they should be aware of any changes." She also reminds people that "the empty seat is first-come, first-serve" — an opportunity she once embraced on a Rome flight.

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