It was plane madness.

Chaos erupted on JetBlue’s red-eye flight from Portland, Ore., to JFK yesterday when a drunk allegedly urinated on a sleeping 11-year-old girl.

The youngster was traveling with her sister and dad, and had been left alone for a few minutes while the others used the lavatories.

Robert Vietze, 18, of South Warren Vt., stumbled from his seat five rows behind her and emptied his bladder, a witness said.

“I was drunk, and I did not realize I was pissing on her leg,” the 6-foot-4, 195-pound Vietze said, according to law-enforcement sources. He later claimed to have consumed eight alcoholic beverages.

The girl’s father caught Vietze midstream.

“I woke up to this man yelling and literally looking like he was about to punch this kid in the face,” said the witness, who asked not to be identified.

“The father was screaming, ‘F – – k that kid! I don’t want him near my family!’ ” the passenger said.

Flight attendants separated the pair and removed Vietze to the back of the plane. They attempted to clean up the mess with liquid soap from the bathrooms, and helped to comfort the traumatized girl.

But the 5½-hour flight from hell was not over yet.

Roughly an hour before the plane landed, another passenger began to complain of chest pains, then vomited.

“Is anybody on this flight a nurse or a doctor?” the pilot said over the public-address system. “We have a medical emergency.”

With no volunteers, the flight crew kept the man calm and tried to tidy him up, again raiding the liquid-soap container.

“The pilots kept coming out of the cockpit to talk to the flight crew about what was going on,” the witness said. “When we landed, the pilot warned us that police were coming.”

Six Port Authority cops met the plane at the gate at around 6:30 a.m.

Two escorted the ill passenger off, and four took Vietze into custody.

Vietze was issued a federal summons for indecent exposure and released.

Additional reporting by Philip Messing

don.kaplan@nypost.com

