(NEW YORK POST) – Remaining calm in stressful situations, dealing with tricky customers and long hours in the sky.

Flight attendants work hard — but a new airline job ad expects even more of hopeful applicants.

“Janet airlines,” which flies US government workers from Las Vegas to the mysterious Area 51 in Nevada, is looking for cabin crew who qualify for “top secret government security clearance.”

Shrouded in mystery, the airline’s fleet consists of unbranded planes operated by the US Air Force.

And, in a job advertisement posted on the website of private defense contractor AECOM, candidates must be able to deal with unusual incidents like hijackings or bomb threats.

On top of duties expected of regular cabin crew such as safety demonstrations, cleaning and emergency procedures, applicants must keep quiet about where they’re going and what they’re doing.

Janet airlines wasn’t named after a mysterious woman — it stands for “Just Another Non-Existent Terminal” — but other than that very little is known about it.

Flight tracking radar shows some of the flights, with call signs starting XXX, making the 45-minute journey to the nuclear facility at Tonopah, which has been the focus of many conspiracy theories.

Other brief flights go to an unspecified destination nearby — believed to be the Area 51 facility famous with alien hunters.

The highly classified site at Groom Lake is believed to be used to test experimental aircraft and “black projects” weapons systems.

Its existence was only acknowledged publicly for the first time in 2005.

Conspiracy theorists believe the top-secret military base contains the remains of an alien spaceship that crashed in the 1940s.

No one aboard a Janet flight is allowed to reveal where they are going or what their job is.

Some conspiracy theorists believe the area holds the remains of a crashed alien spaceship, but an extraterrestrial expert who used to investigate UFOs for the British Ministry of Defence believes there is little to the rumors.

Nick Pope, author of “Encounter in Rendlesham Forest,” said: “The UFO and conspiracy theory community think it’s the place where crashed UFOs are kept and where the US military are trying to back-engineer this alien technology.

“Sadly, despite the rumors, I’ve seen no evidence that we’ve recovered any extraterrestrial technology.”

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