Image: Dreamworks Pictures

When you’re travelling, there’s nothing more reassuring than being warmly greeted by a flight attendant as you step onto the plane.

They’re always smiling broadly… but what are airline staff really thinking as you board? Flight attendant Gaea Peregrinor spilled the beans in a response to a Quora question – and it turns out there’s a lot being masked by that friendly “Hello”.

“Consider that air travel is fraught with inherent danger, made more so by the political climate of the world today, one must be constantly alert and aware of one’s situation. When I greet people, you better believe that I’m always very aware of each passenger who steps through the door of the aircraft,” she says.

Here are the nine things Peregrinor says a flight attendant will silently assess:

1. Your attitude

While you’re struggling to get your ticket and seat number out, they’re making some quick but important assessments about your character from both your body and verbal language.

“I’m working out what attitude do I get from this person? Helpful? Belligerent? Withdrawn? If someone boards the plane with hateful and nasty attitude toward the crew, that’s a concern that needs to be addressed before departure,” Peregrinor writes.

These measures help identify what you might need during the flight, your role in an emergency or whether you might be the cause of any issues.

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2. Your fitness levels

“If I see someone who is muscular, powerful, strong, physically fit, I memorise his/her face and make a mental note of where they are sitting,” she says.

Don’t flatter yourself – it’s nothing to do with romance, but rather singling you out to be of assistance in an emergency.

“I consider this person a resource for me. In the event of an attack on the flight or on me, these are my ‘go-to’ people. If a situation looks like it could develop, I’ll privately and discreetly ask one of these people if they would be willing to help us if necessary,” she says.

This might involve restraining an unruly passenger or any heavy lifting. (Post continues after gallery.)

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3. Whether you’re intoxicated

An intoxicated person can cause trouble anywhere. On a plane, the chance for problems is even greater. If you’re visibly inebriated, a flight attendant will assess the situation, and either keep an eye on you and limit your drinking onboard or even refuse to depart with you on board.

4. Whether you have any disabilities.

This is primarily to ensure that people are not wrongfully seated in an exit row, where assistance is required in emergency situations.

“They need to be able to physically lift a heavy hatch or open a heavy door” she writes.

5. Your language ability

It’s a similar safety issue if you can’t understand the airline’s language. “If they cannot understand English, they cannot understand shouted commands, nor can they read the instructions on how to open the exits,” she says.

6. Whether you're an airline employee.

A key thing a flight attendant will research and look out for are if any passengers who are fellow airline employees and crew members. This means they're trained for emergency situations, and can therefore immediately help out the team. While it sounds extreme, this knowledge could mean the difference between life and death.

"When United flight 232 crashed in Sioux City Iowa in 1989, it was a disaster that should have killed everyone on the plane. But when the problems began, the head flight attendant remembered that an employee, a pilot, was riding in the coach cabin. She told the captain, who told her to ask him for his help. It was his assistance in the cockpit that helped save so many lives," Peregrinor says.

7. If you're sick

If you're harboring an illness or not looking well, flight attendants will know.

"I’ve had passengers board who look pasty and pale, deathly ill. We removed them; nobody wants their flu germs!" she says. (Post continues after gallery.)

Memorable plane scenes from pop culture

Meet the Parents

Gaylord Focker: This is not raising my voice, THIS IS RAISING MY VOICE!

Spy

Susan Cooper: And heres to you, you may not be an owl but you will always be a hoot to me. Rayna Boyanov: What a stupid stupid fucking toast, youre delightful.

Were the Millers

Brad: Family meeting, in the back!

Up in the Air

Ryan Bingham: "All the things you probably hate about travelling, the recycled air, the artificial lighting, the digital juice dispensers, the cheap sushi - are warm reminders that I am home.

Anger Management

Dave Buznik: IM CALM!!

When Harry Met Sally

How long do you like being held afterwards? All night right?

Bridesmaids

Annie: There is a colonial woman on the wing. There is something theyre not telling us. She was out there churning butter. She was churning butter!