The bird-flipping, jet-skiing ex-NYPD cop charged in the multi-million dollar pension fraud scam meekly surrendered Thursday morning in Manhattan Supreme Court.

Glenn Lieberman, 48, had a scarf covering his face and declined comment as he silently walked into the courthouse with his lawyers about 8:30 a.m. for his arraignment on larceny charges.

The former Brooklyn anti-gang cop allegedly scammed $175,758 in undeserved Social Security Disability payments after claiming he suffered from “depression and panic attacks” while working at Ground Zero after 9/11 – though a former colleague said he never worked at the hallowed site.

And investigators from the Manhattan District Attorney Cyrus Vance’s office discovered a social media photo of a grinning Lieberman zooming along on a yellow jet ski while shooting a double middle finger salute at the camera.

Lieberman is one of scores of ex-cops and FDNY firefighters busted in the stunning scam, along with four ringleaders who allegedly coached them on how to fake mental illness and helped them prepare their bogus claims.

Scheming siblings and a married couple were also allegedly in on the sickening scam, in which many other retired cops and firefighters also faked Sept. 11 trauma to score disability benefits, The Post has learned.

Brothers Vincent and Darrin LaMantia, siblings Karen, Kevin and Thomas Galimi and spouses John Kellett and Arlene Mellett claimed psychiatric ailments kept them from earning a living, according to court papers.

Vance said they were part of scheme in which 106 fraudsters exploited the system to score more than $21 million in unwarranted disability pensions.

Others yet to be arrested also participated as far back as 1988, pushing the total cost to taxpayers to about $400 million, prosecutors said.

Like Lieberman, many of the scammers continued to live fun-packed lives of leisure.

Vincent LaMantia, 43, is the most brazen. Though he claims to have suffered crippling mental problems, he can be seen in a YouTube video giving a motivational speech on, of all subjects, getting rich quick.

“Your positive mental attitude will make you a ton of money . . . Your smile will make you a fortune!” he tells the cheering audience. The clip was posted last year, but it was not clear when it was made.

Vincent has been accused of wrongly taking $148,000 in benefits from May 2010 to June 2013. Officials have not given details of why he claimed to be a mental wreck.

He wasn’t always feeling blue. In 1996, Vincent appeared in Cosmopolitan magazine’s “Bachelor of the Month” calendar.

“I’m not going to lie to you, I like the attention,” Vincent, who was a cop in the Brooklyn South Precinct, said at the time.

There was no answer at his Staten Island home in an attempt to reach him for comment.

His brother Darrin, 46, is a deep-sea fisherman and charter-boat captain who’s run tournaments in which anglers hooked massive blue sharks. The ex-cop didn’t return phone messages.

The Galimi siblings, who all worked for the NYPD, are accused of stealing more than $596,000, with more than $287,000 going to Thomas, who began collecting benefits in 2002.

A young woman who answered the phone at Karen’s house insisted, “Nobody is guilty,” while Kevin’s lawyer, Lou La Pietra, said: “My client is one of the few who did nothing wrong.”

Husband-and-wife, ex-cops John Kellett and Arlene Mellett — who have homes in Long Island and Florida — are charged with ripping off more than $300,000. They didn’t return messages seeking comment.

The ringleaders, ex-cops Joseph Esposito and John Minerva, along with pension expert Thomas Hale and lawyer Raymond Lavallee, are accused of supplying a veritable forest of fibs.