A boozy floozy flying Virgin Atlantic to Vegas with her parents joined the mile-high club with the man beside her — and the pair got so loud in the bathroom, flight attendants busted through the door.

The woman, a Brit in her 20s, then spewed profanities at the fuming crew members, who had to handcuff her to her seat for the rest of the flight.

“She was traveling with her mum and dad, and she started getting heated with the guy sitting next to her,’’ a passenger told London’s Sun newspaper.

“They went to the bathroom, and people could hear loud noises. The cabin crew forced the door open. Then she really kicked off, screaming drunken abuse. She was shackled to her seat.”

The tawdry tryst occurred on a nearly 11-hour London-to-Vegas flight last week, the Sun said.

The woman was hauled off the plane after landing, then given a warning by cops and let go, witnesses said.

Virgin’s CEO, Sir Richard Branson, once famously hinted that mile-high sex was OK by him, sniffing, “We’re not the type of airline that bangs on bathroom doors.”