All hell broke loose on a recent flight when a drunken woman described as a “demon” demanded a Pepsi – but was told that only fruit juice was being served.

The unidentified Spanish woman began screaming and taking shots from a flask right after boarding the TAP Air Portugal flight in Lisbon for a trip to Malaga on March 9, according to the Daily Mail.

But the turbulence really erupted when flight attendants informed her that they had no Pepsi, only fruit juice.

“Her hands had turned into claws. She looked like a demon. She was the worst passenger I have ever seen on an airline and I fly quite a lot,” a 38-year-old British tourist told the outlet.

“She was getting out of her seat – her face was bright red,” the fashion designer said. “The way she was acting, it was like she was possessed.”

The unhinged woman is believed to have flown into a rage because she wanted to mix the soft drink with the booze in her flask.

The man said that after boarding late, the woman also got into an argument with a flight attendant about putting her bag in the cargo hold.

“Stewardesses were telling her you have to put it away but she was like ‘no!’ She started speaking English and said, ‘I have my books, I have my jewelry, I have my money in there — I need my bag,’” he said.

The captain later left the cockpit to speak with the woman and handed her a note banning her from the airline, the man said.

“She started screaming more. She was jabbering that her house was in Spain and that she was Spanish,” he said.

In Malaga, police boarded the plane to arrest the woman, whom they labeled a “banshee.”

“This was an unruly passenger situation and all required procedures were followed,” airline spokeswoman Marisa Ferreria told The Post in a statement.