Paris Hilton's Bratty Brother Conrad: Did He Really Call Fellow Passengers "Peasants"?

But will Conrad Hilton see a day in jail?

You won't believe what the FBI says 21-year-old rich kid Conrad Hilton, who is Paris Hilton's bratty brother, did on board a wild, drug-fueled flight from London to Los Angeles.

Passenger Patricia Mitchell witnessed Conrad Hilton threatening flight attendants and acting like a crazy person during the eleven-hour non-stop flight.

She told INSIDE EDITION, "It was insane. I was actually concerned he was having a psychotic breakdown. I mean, I was genuinely concerned. Every sentence contained the F-word. He was beyond verbally abusive, he was psychically menacing."

An FBI report says Paris' brother "smoked marijuana on board", told a flight attendant: "I am going to [expletive] kill you," and called the rest of us "peasants."

He is quoted as saying, "I will [expletive] own anyone on this flight. They are peasants."

The FBI says that Conrad was given a written warning to stop his disruptive behavior, but he just tore it up and boasted he had been banned from other airlines. When, after several hours, he finally fell asleep, the captain ordered that Conrad to be handcuffed in his seat. When the plane landed in Los Angeles, he was arrested.

Conrad Hilton was charged with a federal crime: interfering with a flight crew, which carries a maximum sentence of 20 years in prison.

But, reports that Conrad Hilton won't serve a single day in jail. The charge was plea bargained down to a misdemeanor and he is expected to get just six months probation.

That's even less than the 18 days in jail his sister, Paris, famously served for a probation violation stemming from a 2007 DUI arrest.

And potty-mouth Conrad told a reporter outside court, "you're a [expletive]," when the reporter asked, "any comment?"

The reporter asked him, "I'm a [expletive]?"

Conrad responded, "Yeah."

For passenger Patricia Mitchell, who once worked as a TV broadcaster for the BBC and is now a life-coach, in her opinion the plea deal is not justice.

Mitchell added, "Wow, is that what privilege does that you think that's OK? It's not right. It's just not right."